八上8-11单元单元检测
八上英语Unit8 单元检测卷(含答案)
Unit8 单元检测卷(含答案)一、单项选择(15小题,每小题1分,共15分)1. —________ apples do we need to make fruit salad?—Let me think...We need three apples.A. How longB. How oftenC. How muchD. How many2. Pour the milk ________ the blender.A. ofB. intoC. onD. at3. How many ______ can you see in the picture?A. boxB. booksC. manD. woman4. Lucy put a lot of _____ in _____ of tea.A. sugar, the two cupB. sugars, the two cupsC. sugar, the two cupsD. sugars, the cups5. —Why not ____ some sugar ____ the coffee? - That sounds great.A. put, atB. add, toC. add, withD. add, /6. —Can I fill the box ________ my model cars?—I’m afraid not. It’s full ________ my school things.A. with; withB. of; ofC. of; withD. with; of7. How beautiful the place is! I really want to stay here for ________ days.A. two anotherB. other twoC. another twoD. two other8. Add some ________ to your water and it will taste better.A. cornB. pepperC. honeyD. lettuce9. There _____ two pieces of bread on the table and there _____ some cheese on the slices.A. are; areB. are; isC. is; isD. is; are10. Tina tried many times, and _______ succeeded.A. firstB. nextC. finallyD. hardly11. Can I _________ the TV, Dad? I want to watch the sports news.A. turn offB. turn onC. turn downD. turn up12. It’s 7:00 a.m. The air is fresh. It’s a good time ________.A.exercise B.to exercise C.exercising D.to exercising 13. For this reason, we’ll have to wait for ________ three weeks for the results. A.another B.more C.other D.much14. —Sorry, I’m late.—________ tell me the bus broke down again!A. Never toB. NotC. Don’tD. No15. —Well, ________! The class is over.—Bye, Miss Yang.A. that’s OKB. that’s itC. it’s nothingD. it’s all right二、完形填空(10小题,每小题1分,共10分)先通读短文,掌握其大意,然后从A、B、C、D四个选项中选出一个可以填入相应空白处的最佳答案。
【精品】人教版八年级数学上册第11章三角形单元检测题(有答案)【3套】试题
人教版八年级数学上册第11章三角形单元检测题(有答案)一.选择题(共10小题,每小题3分,满分30分)1.将一个三角形纸片剪开分成两个三角形,这两个三角形不可能()A.都是直角三角形B.都是钝角三角形C.都是锐角三角形D.是一个直角三角形和一个钝角三角形2.若线段AM、AN分别是△ABC中BC边上的高线和中线,则()A.AM>AN B.AM>AN或AM=ANC.AM<AN D.AM<AN或AM=AN3.下列图形具有稳定性的是()A.B.C.D.4.下列各组数可能是一个三角形的边长的是()A.4,4,9 B.2,6,8 C.3,4,5 D.1,2,3 5.如图,∠A=65°,∠B=75°,将纸片的一角折叠,使点C落在△ABC外,若∠2=18°,则∠1的度数为()A.50°B.98°C.75°D.80°6.在△ABC中,∠A==∠C,则这个三角形是()A.锐角三角形B.等腰三角形C.钝角三角形D.含30°角的直角三角形7.在△ABC中,若满足下列条件,则一定不是直角三角形的是()A.∠A=∠B+∠CB.∠A=∠C﹣∠BC.一个外角等于与它相邻的内角D.∠A:∠B:∠C=1:3:58.如图所示,在△ABC中,∠C=90°,则∠B为()A.15°B.30°C.50°D.60°9.将一个多边形纸片沿一条直线剪下一个三角形后,变成一个六边形,则原多边形纸片的边数不可能是()A.5 B.6 C.7 D.810.设BF交AC于点P,AE交DF于点Q.若∠APB=126°,∠AQF=100°,则∠A ﹣∠F=()A.60°B.46°C.26°D.45°二.填空题(共8小题,每小题3分,满分24分)11.三角形的三边之比是3:4:5,周长是36cm,则最长边比最短边长.12.如图,已知BD是△ABC的中线,AB=5,BC=3,且△ABD的周长为11,则△BCD 的周长是.13.空调安装在墙上时,一般都会采用如图所示的方法固定,这种方法应用的几何原理是.14.若△ABC的周长为18,其中一条边长为4,则△ABC中的最长边x的取值范围为.15.如图,在△ABC中,∠B=60°,∠BAC与∠BCA的三等分线分别交于点D、E两点,则∠ADC的度数是.16.如图,CE平分∠ACD,∠A=40°,∠B=30°,∠D=104°,则∠BEC=.17.如图,直线a∥b,Rt△ABC的直角顶点C在直线b上,∠2=70°,∠1=.18.如果一个多边形的边数增加1,它的内角和就增加十分之一,那么这个多边形的边数,三.解答题(共8小题,满分66分)19.(6分)“五一”黄金周,小梦一家计划从家B出发,到景点C旅游,由于BC之间是条湖,无法通过,如图所示只有B﹣A﹣C和B﹣P﹣C两条路线,哪一条比较近?为什么?(提示:延长BP交AC于点D)20.(6分)若三角形的三边长分别是2,x,10,且x是不等式的正偶数解,试求第三边的长x.21.(6分)如图,已知,在△ABC中,∠C=∠ABC,BE⊥AC,∠DBE=60°,求∠C 的度数.22.(6分)如图∠A=∠B,∠C=α,DE⊥AC于点E,FD⊥AB于点D.(1)若∠EDA=25°,则∠EDF=°;(2)若∠A=65°,则∠EDF=°;(3)若α=50°,则∠EDF=°;(4)若∠EDF=65°,则α=°;(5)∠EDF与α的关系为.23.(8分)如图,在四边形ABCD中,∠B=50°,∠C=110°,∠D=90°,AE⊥BC,AF是∠BAD的平分线,与边BC交于点F.求∠EAF的度数.24.(10分)如图,已知六边形ABCDEF的每个内角都相等,连接AD.(1)若∠1=48°,求∠2的度数;(2)求证:AB∥DE.25.(12分)已知△ABC中,∠A=60°,∠ACB=40°,D为BC边延长线上一点,BM 平分∠ABC,E为射线BM上一点.如图1,连接CE,①若CE∥AB,求∠BEC的度数;②若CE平分∠ACB,求∠BEC的度数.26.(12分)如图1,已知两条直线AB,CD被直线EF所截,分别交于点E,点F,EM 平分∠AEF交CD于点M,且∠FEM=∠FME.(1)直线AB与直线CD是否平行,说明你的理由;(2)如图2,点G是射线MD上一动点(不与点M,F重合),EH平分∠FEG交CD 于点H,过点H作HN⊥EM于点N,设∠EHN=α,∠EGF=β.①当点G在点F的右侧时,若β=60°,求α的度数;②当点G在运动过程中,α和β之间有怎样的数量关系?请写出你的猜想,并加以证明.参考答案一.选择题1.解:如图,沿三角形一边上的高剪开即可得到两个直角三角形.如图,钝角三角形沿虚线剪开即可得到两个钝角三角形.如图,直角三角形沿虚线剪开即可得到一个直角三角形和一个钝角三角形.因为剪开的边上的两个角互补,故这两个三角形不可能都是锐角三角形.故选:C.2.解:如图,∵AM⊥BC,∴根据垂线段最短可知:AM≤AN,故选:D.3.解:∵三角形具有稳定性,∴A选项符合题意而B,C,D选项不合题意.故选:A.4.解:A、因为4+4<9,所以本组数不能构成三角形.故本选项错误;B、因为2+6=8,所以本组数不能构成三角形.故本选项错误;C、因为3+4>5,所以本组数可以构成三角形.故本选项正确;D、因为1+2=3,所以本组数不能构成三角形.故本选项错误;故选:C.5.解:∵∠A=65°,∠B=75°,∴∠C=180°﹣∠A﹣∠B=180°﹣65°﹣75°=40°;又∵将三角形纸片的一角折叠,使点C落在△ABC外,∴∠C′=∠C=40°,∵∠3+∠2+∠5+∠C′=180°,∠5=∠4+∠C=∠4+40°,∠2=18°,∴∠3+18°+∠4+40°+40°=180°,∴∠3+∠4=82°,∴∠1=180°﹣82°=98°.故选:B.6.解:∵∠A==∠C,∴∠B=2∠A,∠C=3∠A,又∵∠A+∠B+∠C=180°,∴∠A+2∠A+3∠A=180°,解得:∠A=30°,∴∠C=3∠A=3×30°=90°,故选:D.7.解:A、∵∠A=∠B+∠C,∠A+∠B+∠C=180°,∴∠A=90°,∴△ABC是直角三角形,故本选项不符合题意.B、∵∠A=∠C﹣∠B,∠A+∠B+∠C=180°,∴∠C=90°,∴△ABC是直角三角形,故本选项不符合题意.C、∵一个外角等于与它相邻的内角,又这两个角互补,∴相邻的内角是90°,∴三角形是直角三角形,故本选项不符合题意.D、∵∠A:∠B:∠C=1:3:5,∴∠A=20°,∠B=60°,∠C=100°,∴△ABC是钝角三角形,故本选项符合题意,故选:D.8.解:如图所示,在△ABC中,∠C=90°,则x+2x=90°.x=30°.所以2x=60°,即∠B为60°.故选:D.9.解:如图可知,原来多边形的边数可能是5,6,7.不可能是8.故选:D.10.解:如图:∵∠1=∠APB﹣∠A=126°﹣∠A,∠2=180°﹣∠AQF﹣∠F=180°﹣100°﹣∠F =80°﹣∠F;∵∠1=∠2,∴126°﹣∠A=80°﹣∠F;∴∠A﹣∠F=46°.故选:B.二.填空题11.解:由题意,设三边分别为3xcm,4xcm,5xcm,则3x+4x+5x=36,解得x=3,三边分别为9cm,12cm,15cm.故最长的边长比最短的边长长6cm.故答案是:6cm.12.解:∵BD是△ABC的中线,∴AD=CD,∵△ABD的周长为11,AB=5,BC=3,∴△BCD的周长是11﹣(5﹣3)=9,故答案为9.13.解:这种方法应用的数学知识是:三角形的稳定性,故答案为:三角形具有稳定性.14.解:∵△ABC的周长为18,其中一条边长为4,这个三角形的最大边长为x,∴第三边的长为:18﹣4﹣x=14﹣x,∴x>4且x>14﹣x,∴x>7,根据三角形的三边关系,得:x<14﹣x+4,解得:x<9;∴7<x<9,故答案为:7<x<9.15.解:∵在△ABC中,∠B=60°,∴∠BAC+∠BCA=180°﹣∠B=120°.∵∠BAC与∠BCA的三等分线分别交于点D、E两点,∴∠DAC=∠BAC,∠DCA=∠BCA,∴∠DAC+∠DCA=(∠BAC+∠BCA)=80°,∴∠ADC=180°﹣(∠DAC+∠DCA)=180°﹣80°=100°.故答案为:100°.16.解:延长CD交AB于F,∠BDC是△BDF的一个外角,则∠BFD=∠BDC﹣∠B=104°﹣30°=74°,同理,∠ACF=∠BFD﹣∠A=74°﹣40°=34°,∵CE平分∠ACD,∴∠ECA=∠ACF=17°,∴∠BEC=∠A+∠ECA=40°+17°=57°,故答案为:57°.17.解:∵a∥b,∴∠3=∠2=70°,∴∠1=180°﹣90°﹣70°=20°,故答案为:20°.18.解:设多边形的边数是n,根据题意得:180(n+1﹣2)=180(n﹣2)(1+),解得:n=12.故答案是:12.三.解答题19.解:如图,延长BP交AC于点D.∵△ABD中,AB+AD>BD=BP+PD,△CDP中,PD+CD>CP,∴AB+AD+PD+CD>BP+PD+CP,即AB+AD+CD>BP+CP,∴AB+AC>BP+CP,∴B﹣P﹣C路线较近.20.解:原不等式可化为5(x+1)>20﹣4(1﹣x),解得x<11,∵x是它的正整数解,∴根据三角形第三边的取值范围,得8<x<12,∵x是正偶数,∴x=10.∴第三边的长为10.21.解:∵BE⊥AC,∴∠AEB=90°,∵∠DBE=60°,∴∠A=90°﹣60°=30°,∴∠C=∠ABC=(180°﹣30°)=75°.22.解:(1)∵DF⊥AB,∴∠ADF=90°,∴∠EDF=90°﹣∠EDA=65°.(2)∵DE⊥AC,∴∠AED=90°,∴∠ADE=90°﹣65°=25°,∴∠EDF=65°.(3)∵α=50°,∴∠A=∠B=(180°﹣50°)=65°,∴∠DEF=65°.(4)∵∠EDF=65°,∴∠ADE=90°﹣65°=25°,∴∠A=∠B=65°,∴α=180°﹣130°=50°(5)∵∠A=∠B,∠C=α∴∠A=∠B=(180°﹣α)=90°﹣α,∵DE⊥AC于点E,FD⊥AB于点D,∴∠AED=∠FDB=90°∴∠EDA=∠BFD=90°﹣(90°﹣α)=α,∴∠EDF=90°﹣∠EDA=90°﹣α.故答案为(1)65°;(2)25°;(3)65°;(4)50°;(5)90°﹣0.5a;23.解:∵AE⊥BC,∴∠AEC=∠AEB=90°,∵∠B=50°,∴∠BAE=180°﹣90°﹣50°=40°,∵∠C=110°,∠D=90°,∴∠DAE=360°﹣∠D﹣∠C﹣∠AEC=70°,∴∠DAB=∠BAE+∠DAE=40°+70°=110°,∵AF平分∠DAB,∴∠FAB=∠DAB=110°=55°,∴∠EAF=∠FAB﹣∠BAE=55°﹣40°=15°.24.解:(1)∵六边形ABCDEF的各内角相等,∴一个内角的大小为,∴∠E=∠F=∠BAF=120°.∵∠FAB=120°,∠1=48°,∴∠FAD=∠FAB﹣∠DAB=120°﹣48°=72°.∵∠2+∠FAD+∠F+∠E=360°,∠F=∠E=120°,∴∠ADE=360°﹣∠FAD﹣∠F﹣∠E=360°﹣72°﹣120°﹣120°=48°.(2)证明:∵∠1=120°﹣∠DAF,∠2=360°﹣120°﹣120°﹣∠DAF=120°﹣∠DAF,∴∠1=∠2,∴AB∥DE.25.解:①如图1,∵∠A=60°,∠ACB=40°,∴∠ABC=80°,∵BM平分∠ABC,∴∠ABE=∠ABC=40°,∵CE∥AB,∴∠BEC=∠ABE=40°;②如图2,∵∠A=60°,∠ACB=40°,∴∠ABC=80°,∵BM平分∠ABC,CE平分∠ACD,∴∠CBE=∠ABC=40°,∠ECB=∠ACB=20°,∴∠BEC=180°﹣∠ECB﹣∠CBE=180°﹣20°﹣40°=120°.26.解:(1)结论:AB∥CD.理由:如图1中,∵EM平分∠AEF交CD于点M,∴∠AEM=∠MEF,∵∠FEM=∠FME.∴∠AEM=∠FME,∴AB∥CD.(2)①如图2中,∵AB∥CD,∴∠BEG=∠EGH=β=60°,∴∠AEG=120°,∵∠AEM=∠EMF,∠HEF=∠HEG,∴∠HEN=∠MEF+∠HEF=∠AEG=60°,∵HN⊥EM,∴∠HNE=90°,∴∠EHN=90°﹣∠HEN=30°.②猜想:α=β.理由:∵AB∥CD,∴∠BEG=∠EGH=β,∴∠AEG=180°﹣β,∵∠AEM=∠EMF,∠HEF=∠HEG,∴∠HEN=∠MEF+∠HEF=∠AEG=90°﹣β,∵HN⊥EM,∴∠HNE=90°,∴α=∠EHN=90°﹣∠HEN=β.人教版八年级上册第十一章三角形单元测试(3)一、选择题(每题3分,共30分)1.如图,∠1的大小等于()A.40°B.50°C.60°D.70°(第1题)(第4题)2.下列长度的三条线段,能组成三角形的是()A.2 cm,3 cm,4 cm B.2 cm,3 cm,5 cmC.2 cm,5 cm,10 cm D.8 cm,4 cm,4 cm3.在△ABC中,能说明△ABC是直角三角形的是()A.∠A:∠B :∠C=1 :2 :2 B.∠A :∠B :∠C=3 :4 :5 C.∠A :∠B :∠C=1 :2 :3 D.∠A :∠B :∠C=2 :3 :4 4.如图,在△ABC中,∠A=80°,∠B=40°,D,E分别是AB,AC上的点,且DE∥BC,则∠AED的度数是()A.40°B.60°C.80°D.120°5.在下列各图形中,分别画出了△ABC中BC边上的高AD,其中正确的是()6.如图,△ABC的角平分线BE,CF相交于点O,且∠FOE=121°,则∠A的度数是()A.52°B.62°C.64°D.72°(第6题) (第7题)(第9题) (第10题)7.如图,在△ABC中,∠C=90°,D,E是AC上两点,且AE=DE,BD平分∠EBC.下列说法不正确...的是()A.BE是△ABD的中线B.BD是△BCE的角平分线C.∠1=∠2=∠3 D.BC是△ABE的高8.一个多边形的内角和比它的外角和的3倍少180°,这个多边形的边数是()A.8 B.7 C.6 D.59.如图,在△ABC中,∠C=75°,若沿图中虚线截去∠C,则∠1+∠2=()A.360°B.180°C.255°D.145°10.如图,∠A,∠B,∠C,∠D,∠E五个角的和等于()A.90°B.180°C.360°D.540°二、填空题(每题3分,共24分)11.人站在晃动的公交车上,若分开两腿站立,还需伸出一只手抓住栏杆才能站稳,这是利用了___________________________________________________.12.正十边形每个外角的度数是________.13.已知三角形三边长分别为1,x,5,则整数x=________.14.将一副三角尺按如图所示放置,则∠1=________.(第14题)(第16题)(第18题)15.一个多边形从一个顶点出发可以画9条对角线,则这个多边形的内角和为________.16.如图,在△ABC中,AD是BC边上的中线,BE是△ABD中AD边上的中线,若△ABC的面积是24,则△ABE的面积是________.17.当三角形中一个内角α是另一个内角β的一半时,我们称此三角形为“半角三角形”,其中α称为“半角”.若一个“半角三角形”的“半角”为20°,则这个“半角三角形”最大内角的度数为________. 18.已知△ABC ,有下列说法:(1)如图①,若P 是∠ABC 和∠ACB 的平分线的交点,则∠P =90°+12∠A ; (2)如图②,若P 是∠ABC 和外角∠ACE 的平分线的交点,则∠P =90°-∠A ; (3)如图③,若P 是外角∠CBF 和∠BCE 的平分线的交点,则∠P =90°-12∠A . 其中正确的有______个.三、解答题(23题12分,24题14分,其余每题10分,共66分)19.如图,一艘轮船在A 处看见巡逻艇C 在其北偏东62°的方向上,此时一艘客船在B 处看见巡逻艇C 在其北偏东13°的方向上.试求此时在巡逻艇上看这两艘船的视角∠ACB 的度数.(第19题)20.如图,BD ,CE 是△ABC 的两条高,它们交于O 点. (1)∠1和∠2的大小关系如何?并说明理由. (2)若∠A =50°,∠ABC =70°,求∠3和∠4的度数.(第20题)21.如图,已知AD是△ABC的角平分线,CE是△ABC的高,AD,CE相交于点P,∠BAC=66°,∠BCE=40°.求∠ADC和∠APC的度数.(第21题)22.如图,六边形ABCDEF的内角都相等,CF∥AB.(1)求∠FCD的度数;(2)求证AF∥CD.(第22题)23.如图,在△ABC中,∠A=30°,一块直角三角尺XYZ放置在△ABC上,恰好三角尺XYZ的两条直角边XY,XZ分别经过点B,C.(1)∠ABC+∠ACB=________,∠XBC+∠XCB=________,∠ABX+∠ACX=________.(2)若改变直角三角尺XYZ的位置,但三角尺XYZ的两条直角边XY,XZ仍然分别经过点B,C,则∠ABX+∠ACX的大小是否变化?请说明理由.(第23题)24.已知∠MON=40°,OE平分∠MON,点A,B,C分别是射线OM,OE,ON上的动点(点A,B,C均不与点O重合),连接AC交射线OE于点D,设∠OAC=x°.(1)如图①,若AB∥ON,则①∠ABO的度数是________.②当∠BAD=∠ABD时,x=________;当∠BAD=∠BDA时,x=________.(2)如图②,若AB⊥OM,是否存在这样的x的值,使得△ADB中有两个相等的角?若存在,求出x的值;若不存在,说明理由.(第24题)答案一、1.D 2.A 3.C 4.B 5.B 6.B7.C8.B9.C10.B二、11.三角形具有稳定性12.36°13.514.105°15.1 800°16.617.120°18.2三、19.解:由题意可得AD∥BF,∴∠BEA=∠DAC=62°.∵∠BEA是△CBE的一个外角,∴∠BEA=∠ACB+∠CBE.∴∠ACB=∠BEA-∠CBE=62°-13°=49°.答:此时在巡逻艇上看这两艘船的视角∠ACB的度数为49°.20.解:(1)∠1=∠2.理由如下:∵BD,CE是△ABC的两条高,∴∠AEC=∠ADB=90°.∵∠A+∠1+∠ADB=180°,∠2+∠A+∠AEC=180°,∴∠1=∠2.(2)∵∠A=50°,∠ABC=70°,∠A+∠ABC+∠ACB=180°,∴∠ACB=60°.∵在△AEC中,∠A+∠AEC+∠2=180°,∴∠2=40°.∴∠3=∠ACB-∠2=20°.∵在四边形AE O D中,∠A+∠AE O+∠4+∠AD O=360°,∠A=50°,∠AE O=∠AD O=90°,∴∠4=130°.21.解:∵CE是△ABC的高,∴∠AEC=90°.∴∠ACE=180°-∠BAC-∠AEC=24°.∵AD是△ABC的角平分线,∴∠DAC=12∠BAC=33°.∵∠BCE=40°,∴∠ACB=40°+24°=64°.∴∠ADC=180°-∠DAC-∠ACB=83°.∴∠A P C=∠ADC+∠BCE=83°+40°=123°.22.(1)解:∵六边形ABCDEF的内角都相等,内角和为(6-2)×180°=720°,∴∠B=∠A=∠BCD=720°÷6=120°.∵CF∥AB,∴∠B+∠BCF=180°.∴∠BCF=60°.∴∠FCD=∠BCD-∠BCF=60°.(2)证明:∵CF∥AB,∴∠A+∠AFC=180°.∴∠AFC=180°-120°=60°.∴∠AFC=∠FCD.∴AF∥CD.23.解:(1)150°;90°;60°(2)∠ABX+∠ACX的大小不变.理由:在△ABC中,∠A+∠ABC+∠ACB=180°,∠A=30°,∴∠ABC+∠ACB=180°-30°=150°.∵∠YXZ=90°,∴∠X BC+∠X CB=90°.∴∠AB X+∠AC X=(∠ABC-∠X BC)+(∠ACB-∠X CB)=(∠ABC+∠ACB)-(∠X BC+∠X CB)=150°-90°=60°.∴∠AB X+∠AC X的大小不变.24.解:(1)①20°②120;60(2)存在.①当点D在线段O B上时,若∠BAD=∠ABD,则x=20;若∠BAD=∠BDA,则x=35;若∠ADB=∠ABD,则x=50.②当点D在射线BE上时,易知∠ABE=110°,又三角形的内角和为180°,∴只有∠BAD=∠BDA,此时x=125.综上可知,存在这样的x的值,使得△ADB中有两个相等的角,且x=20,35,50或125.人教版八年级上册第十一章三角形单元测试(2)一、选择题(每题3分,共30分)1.三角形的三条高所在的直线相交于一点,这个交点的位置在()(A)三角形内(B)三角形外(C)三角形边上(D)要根据三角形的形状才能定2.下列长度的各组线段中,能组成三角形的是()(A)1、2、3(B)1、4、2(C)2、3、4(D)6、2、33.将一副三角板按如图所示的位置摆放在直尺上,则∠1的度数为()A.60°B.65°C.75°D.85°4.一个多边形只有27条对角线,则这个多边形的边数为()(A)8(B)9(C)10(D)115.若正多边形的内角和是540°,则该正多边形的一个外角为()A.45°B.60°C.72°D.90°6.已知一个多边形的内角和为540°,则这个多边形为A.三角形 B.四边形 C.五边形 D.六边形7.如图为矩形ABCD,一条直线将该矩形分割成两个多边形,若这两个多边形的内角和分别为a和b,则a+b不可能是()A.360°B.540°C.630°D.720°8.一个三角形的两边的长分别为3和8,第三边的长为奇数,则第三边的长为()(A) ①5或7 (B) 7 (C) 9 (D) 7或99.如果一个多边形的内角和是外角和的5倍,那么这个多边形的边数是()A.10 B.11 C.12 D.1310.如图,AB∥CD,AD,BC相交于O,∠BAD=35°,∠BOD=76°,则∠C的度数是( )(A) 31° (B) 35° (C) 41° (D) 76°二、填空题(每题3分,共30分)11.如果三条线段a、b、c,可组成三角形,且a=3,b=5,c是偶数,则c的值为.第10题12.△ABC中,已知∠A=800,∠B=700,则∠C= .13.有四条线段,长分别为3cm、5cm、7cm、9cm,如果用这些线段组成三角形,可以组成个三角形.14.如果一个三角形的三个内角的度数比为1∶2∶3,则这个三角形是三角形.15.一个直角三角形两锐角的平分线所夹的钝角为.16.在△ABC中,∠A=50°,∠B=30°,点D在AB边上,连接CD,若△ACD为直角三角形,则∠BCD的度数为度.17.一个多边形的每一个外角都等于360,则该多边形的内角和等于18.用7根火柴棒首尾顺次连接摆成一个三角形,能摆成不同的三角形的个数为_____.19.如图2,将一副直角三角板叠在一起,使直角顶点重合于点O ,则 ∠AOB+∠DOC= .20.如图,在图1中,互不重叠的三角形共有4个,在图2中,互不重叠的三角形共有7个,在图3中,互不重叠的三角形共有10则在第nn 的代数式表示).三、解答题(共60分) 21.(本题6分)如图所示,小明欲从A 地去B 地,有三条路可走:①A →B ;②A →D →B ;③A →C →B .(1)在没有其它因素的情况下,我们可以肯定小明是走①,理由是______.(2)小明绝对不会走③,因为③路程最长,即AC +BC >AD +DB ,你能说明其原因吗?22.(本题6分)正在修建的中山路有一形状如图13所示的三角形空地需要绿化,拟从点A出发,将ABC △分成面积相等的四个三角形,以便种上不同的花草,请你帮助规划出图案.23.(本题7分)一个多边形的内角和比外角和多360度,这是几边形? 24.(本题7分)如图,在△ABC 中,AD 是高,AE 、BF 是角平分线,它们相交于点O BAC =50°,∠C =70°.求∠DAC 和∠BOA 的度数.DABCPIO图1 第20题图 图3 第21题图 DE AB C图1325.(本题8分)如图,求:∠A+∠B+∠C+∠D+∠E+∠F的度数.26.(本题8分)分别测量如图所示的△ABC 和△DEF 的内角 (1)你发现了什么?(2)你有何猜想? (3)通过什么途径说明你的猜想?27.(本题9分)如图,△ABC 中,∠C=90°,∠A=30°. (1)作图:作AB 边上的高CD ,垂足为D ; (2)求∠ACD ,∠BCD ,∠B 的度数;(3)用刻度尺测量BC 和AB ,CD 和AC ,DB 和BC ,将三组线段分别相除(即将BC •的长度除以AB 的长度,CD 的长度除以AC 的长度,DB 的长度除以BC 的长度),你发现了什么规律?28.(本题9分)一块三角形优良品种试验田,现引进四种不同的种子进行对比试验,需要将这块地分成面积相等的四块,请你设计出两种划分方案供选择,画图说明。
(名师整理)数学八年级上册 《第11章 三角形》单元检测试题(含答案解析)
第十一章《三角形》单元测试题一、选择题(每小题只有一个正确答案)1.三角形是()A.由三条线段组成的图形B.由不在同一条直线上的三条线段首尾顺次相接所成的图形C.连接任意三点组成的图形D.以上说法都不对2.已知三角形的两边长分别是4和7,则这个三角形的第三条边的长可能是()A. 12B. 11C. 8D. 33.已知一个三角形三个内角度数的比是1:5:6,则其最大内角的度数为()A.60°B.75°C.90°D.120°4.取一张长方形纸片,按图中所示的方法折叠一角,得到折痕EF,若∠BEF=54°,则∠BFC等于()A.100°B.108°C.118°D.120°5.如图,在△ABC中,∠A=60度,点D,E分别在AB,AC上,则∠1+∠2的大小为()度.A. 140B. 190C. 320D. 2406.如图,△ABC中,∠C=90°,AC=3cm,点P是边BC上的动点,则AP长不可能是()A. 2.5cmB. 3cmC. 4cmD. 5cm7.如果一个三角形两边上的高的交点在三角形的内部,那么这个三角形是()A.锐角三角形B.直角三角形C.钝角三角形D.任意三角形8.自行车采用三角形架结构比较牢固,而能够自由拉开,关闭的活动门采用四边形结构,其原因说法正确的全面的是()A.三角形和四边形都具有稳定性B.三角形的稳定性C.四边形的不稳定性D.三角形的稳定性和四边形的不稳定性9.线段BC上有3个点P1、P2、P3,线段BC外有一点A,把A和B、P1、P2、P3、C 连接起来,可以得到的三角形个数为()A. 8个B. 10个C. 12个D. 20个10.至少有两边相等的三角形是()A.等边三角形B.等腰三角形C.等腰直角三角形D.锐角三角形11.如图,在四边形ABCD中,对角线BD平分∠ABC,若∠ABD=31°,则∠ABC的度数是()A.31°B.61°C.60°D.62°12.如图,已知AB⊥BD,AC⊥CD,∠A=40°,则∠D的度数为()A.40°B.50°C.60°D.70°二、填空题13.观察以下图形,回答问题:(1)图②有个三角形;图③有个三角形;图④有个三角形;…猜测第七个图形中共有个三角形.(2)按上面的方法继续下去,第n个图形中有个三角形(用n的式子表示结论).14.如图,在Rt△ABC中,AC⊥BC,CD⊥AB,∠1=∠2,有下列结论:(1)AC∥DE;(2)∠A=∠3;(3)∠B=∠1;(4)∠B与∠2互余;(5)∠A=∠2.其中正确的有(填写所有正确的序号).15.如图,△ABC中.AE⊥BC于E,AD为BC边上的中线.DF为△ABD中AB边上的中线.已知AB=8cm,AC=5cm,△ABC的面积为8cm2,则(1)△ABD与△ACD的周长之差是;(2)△ABD的面积是;(3)△ADF的面积是.16.如图,一副三角板△AOC和△BCD如图摆放,则∠AOB= .17.如图,已知在△ABC中,∠B与∠C的平分线交于点P.当∠A=70°时,则∠BPC的度数为 .三、解答题18.如图,你能比较∠1与∠2的大小吗?请说明理由.19.在直角三角形中,一个锐角比另一个锐角的3倍还多10°,求这两个锐角的度数.20.如图,(1)写出所有以E为顶点的小于平角的角;(2)写出所有以AE为边的三角形.21.如图所示,D是BA延长线上的点,E是BC延长线上的点,连接CD,∠1=∠2,求证:∠BAC>∠B.22.已知:如图,AB∥CD,求图形中的x的值.23.如图,在△AB C中,点E在AC上,∠AEB=∠ABC.(1)图1中,作∠BAC的角平分线AD,分别交CB、BE于D、F两点,求证:∠EFD=∠ADC;(2)图2中,作△ABC的外角∠BAG的角平分线AD,分别交CB、BE的延长线于D、F两点,试探究(1)中结论是否仍成立?为什么?答案解析1.【答案】B【解析】由不在同一条直线上的三条线段首尾顺次相接所组成的图形叫做三角形,所以答案为B.2.【答案】C【解析】设第三边的长为x cm,根据三角形的三边关系得:7﹣4<x<7+4,即3<x<11,故选C.3.【答案】C【解析】已知三角形三个内角的度数之比,可以设一份为k°,根据三角形的内角和等于180°列方程求三个内角的度数,确定最大的内角的度数.设一份为k°,则三个内角的度数分别为k°,5k°,6k°,根据三角形内角和定理,可知k+5k+6k=180,解得k=15.所以6k=90,即最大的内角是90°.4.【答案】B【解析】∵∠BEF=54°,纸片是长方形,∴∠BFE=90°-54°=36°,由翻折的性质得,∠BFE=∠B′FE=36°,∴∠BFC=180°-2×36°=108°.故选B.5.【答案】D【解析】∵∠A+∠ADE=∠1,∠A+∠AED=∠2,∴∠A+(∠A+∠ADE+∠AED)=∠1+∠2,∵∠A+∠ADE+∠AED=180°,∠A=60°,∴∠1+∠2=60°+180°=240°.故选D.6.【答案】A【解析】已知,在△ABC中,∠C=90°,AC=3cm,根据垂线段最短,可知AP的长不可小于3cm,当P和C重合时,AP=3cm.7.【答案】A【解析】利用三角形高线的位置关系得出:如果一个三角形两边上的高的交点在三角形的内部,那么这个三角形是锐角三角形.故选A.8.【答案】D【解析】根据三角形的三边一旦确定,则形状大小完全确定,即三角形的稳定性;四边形的四边确定,形状大小不一定确定,即四边形的不稳定性.9.【答案】B【解析】能够把组合三角形转换为组合线段的问题,可得到所有的三角形,即在B、P1、P2、P3、C中,任意选两个点和点B组合.从5个点中,任意选2个点组合,组合情况有BP1、BP2、BP3、BC、P1P2、P1P3、P1C、P2P3、P2C、P3C,显然有10种情况.10.【答案】B【解析】本题需要分类讨论:两边相等的三角形称为等腰三角形,该等腰三角形可以是等腰直角三角形,该等腰三角形有可能是锐角三角形,也有可能是钝角三角形;当有三边相等时,该三角形是等边三角形.等边三角形是一特殊的等腰三角形.故选B.11.【答案】D【解析】∵BD平分∠ABC∴∠ABC=2∠ABD,∵∠ABD=31°∴∠ABC=62°.12.【答案】A【解析】∵AB⊥BD,∠A=40°,∴∠AEB=50°,∴∠DEC=50°,又AC⊥CD,∴∠D=40°,故选A.13.【答案】(1)3;5;7;13(2)2n-1【解析】(1)图②有3个三角形;图③有5个三角形;图④有7个三角形;…猜测第七个图形中共有13个三角形.(2)∵图②有3个三角形,3=2×2-1;图③有5个三角形,5=2×3-1;图④有7个三角形,7=2×4-1;∴第n个图形中有(2n-1)个三角形.14.【答案】(1)(2)(3)【解析】∵AC⊥BC,CD⊥AB,∴△ACD与△AC B都为直角三角形,∴∠A+∠1=90°,∠A+∠B=90°,∴∠1=∠B,选项(3)正确;∵∠1=∠2,∴AC ∥DE,选项(1)正确;∴∠A=∠3,选项(2)正确;∵∠1=∠B,∠1=∠2,∴∠2=∠B,即∠2与∠B不互余,选项(4)错误;∠2不一定等于∠A,选项(5)错误;则正确的选项有(1)(2)(3),故答案为:(1)(2)(3).15.【答案】(1)3cm;(2)4cm2;(3)2cm2.【解析】(1)∵AD为BC边上的中线,∴BD=CD,∴△ABD与△ACD的周长之差=(AB+AD+BD)-(AC+AD+CD)=AB-AC=3cm;(2)∵AD为BC边上的中线,∴△ABD的面积=×△ABC的面积=4cm2;(3)∵DF为BC边上的中线,∴△ADF的面积=×△ABD的面积=2cm2,16.【答案】165°【解析】∵∠BDC=60°,∴∠ADO=180°-∠BDC=120°,∴∠OAD=45°,∴∠AOB=∠OAD+∠ADO=165°.故答案为:165°.17.【答案】125°【解析】∵△ABC中,∠A=70°,∴∠ABC+∠ACB=180°-∠A=180°-70°=110°,∴BP,CP分别为∠ABC与∠ACP的平分线,∴∠2+∠4=(∠ABC+∠ACB)=×110°=55°,∴∠P=180°-(∠2+∠4)=180°-55°=125°.故答案为:125°.18.【答案】解:∠1>∠2.理由如下:在△ABC中,∠1>∠ACB,在△CED中,∠ACB>∠2,∴∠1>∠2.【解析】根据三角形的外角大于任何一个和它不相邻的内角进行比较.19.【答案】解:设另一个锐角为x°,则一个锐角为(3x+10)°,由题意得,x+(3x+10)=90,解得x=20,3x+10=3×20+10=70,所以,这两个锐角的度数分别为20°,70°.【解析】设另一个锐角为x°,表示出一个锐角,然后根据直角三角形两锐角互余列方程求解即可.20.【答案】(1) ∠AEF,∠AED,∠DEB,∠DEF,∠AEB.(2)△ABE;△ADE;△AEF.【解析】(1)以E为顶点的角是∠AEF,∠AED,∠DEB,∠DEF,∠AEB.(2)以AE为边的三角形有△ABE;△ADE;△AEF.21.【答案】证明:∵∠B+∠D=∠2,∠1=∠2,∴∠B+∠D=∠1,∴∠1>∠B,∵∠1+∠D=∠BAC,∴∠BAC>∠1,∴∠BA C>∠B.【解析】根据三角形内角和外角的关系可得∠B+∠D=∠2=∠1,进而得到∠1>∠B,再根据∠1+∠D=∠BAC,可得∠BAC>∠1,进而得到∠BAC>∠B.22.【答案】解:∵AB∥CD,∠C=60°,∴∠B=180°-60°=120°,∴(5-2)×180°=x+150°+125°+60°+120°,∴x=85°.【解析】根据平行线的性质先求∠B的度数,再根据五边形的内角和公式求x的值.23.【答案】解:(1)∵AD平分∠BAC,∴∠BAD=∠DAC,∵∠EFD=∠DAC+∠AEB,∠ADC=∠ABC+∠BAD,又∵∠AEB=∠ABC,∴∠EFD=∠ADC;(2)探究(1)中结论仍成立;理由:∵AD平分∠BAG,∴∠BAD=∠GAD,∵∠FAE=∠GAD,∴∠FAE=∠BAD,∵∠EFD=∠AEB-∠FAE,∠ADC=∠ABC-∠BAD,又∵∠AEB=∠ABC,∴∠EFD=∠ADC.【解析】(1)首先根据角平分线的性质可得∠BAD=∠DAC,再根据内角与外角的性质可得∠EFD=∠DAC+∠AEB,∠ADC=∠ABC+∠BAD,进而得到∠EFD=∠ADC;(2)首先根据角平分线的性质可得∠BAD=∠DAG,再根据等量代换可得∠FAE=∠BAD,然后再根据内角与外角的性质可得∠EFD=∠AEB-∠FAE,∠ADC=∠ABC-∠BAD,进而得∠EFD=∠ADC.。
人教版初中英语八年级上册Unit8单元评价检测试卷及答案
人教版初中英语八年级上册Unit8单元评价检测一、单项选择(共15小题;共15.0分)1. --- What do you need to make the tomato noodles?--- onion and tomato, please.A. A; aB. An; anC. A; anD. An; a2. Tom is in good health, because he often exercises and eats a lot of healthy .A. foodB. waterC. pearD. carrot3. --- do you make fruit salad?--- First, cut up the apples, bananas and pears. And then...A. WhenB. WhereC. WhyD. How4. --- What did you eat for breakfast this morning?--- Two and some vegetables.A. chickenB. piece of chickenC. pieces of chickenD. pieces of chickens5. --- water do we need to make the soup?--- Three cups.A. How manyB. How muchC. How longD. How soon6. It's dark(暗的) in the room. Please the light.A. turn onB. turn upC. turn downD. turn off7. " exercise every day, my son. It's good for your health." Dad often said to him.A. TakesB. TakingC. TakeD. To take8. We must cut the tomatoes and put them the blender.A. off; inB. up; intoC. down; intoD. over; in9. --- Can I help you, sir?--- Yeah, but I don't know a banana milk shake. Maybe you can teach me.A. what to doB. when to makeC. how to makeD. why to do10. --- Tom, supper is ready.--- I don't want to eat , Mum. I'm not feeling well.A. everythingB. nothingC. somethingD. anything11. --- How did you celebrate your father's birthday yesterday?--- We celebrated it a big dinner in a restaurant.A. haveB. to haveC. by havingD. to having12. You may fill the turkey these bread pieces.A. inB. byC. withD. to13. --- There little yogurt in the fridge(冰箱). Could you buy some for me, Dick?--- All right, Mom.A. isB. areC. amD. have14. Here two cups milk for you. Help yourself please.A. is; ofB. is; inC. are; ofD. are; in15. --- Let's make tomato and beef noodles.--- .A. Sounds goodB. You're welcomeC. That's rightD. Don't worry二、完形填空(共10小题;共15.0分)Pizza is a kind of popular food. It 16 from Italy. The pizza capital of the world is Naples. The world's first pizza 17 is still there. It 18 in 1830. The best pizza of today has a(n) 19 history. It was first made by a person 20 Raffaele Esposito in the 1880s. This pizza has the same 21 as the Italian flag. The Italian flag is red, white and 22 . The pizza has red tomatoes, white cheese and green herbs.There are many different kinds of pizza today. We can 23 chicken pizza, vegetable pizza, etc. in the restaurant. Some pizza has tomatoes, and some pizza 24 tomatoes. Most pizza is round, 25 some isn't. You can choose any kind you want.16. A. come B. comes C. are D. am17. A. theater B. club C. train D. restaurant18. A. opens B. turns on C. opened D. turned on19. A. long B. short C. excited D. boring20. A. name B. names C. named D. naming21. A. colors B. shape C. time D. recipe22. A. black B. blue C. yellow D. green23. A. order B. make C. do D. sell24. A. has B. doesn't have C. is D. isn't25. A. or B. so C. but D. because三、阅读与表达(判断式)(共5小题;共10.0分)Erica is a twelve-year-old girl. She can make delicious noodles. Here is her recipe for noodles. Try it and taste for yourself!Soup Ingredients:● one cup of orange juice● one cup of lemon juice● one teaspoon of honeyOther Ingredients:● noodles● salt● 3 slices of chicken● some strawberries (cut up)● some green onions (cut up)● some lettuce● 2 slices of cheeseSteps:First, mix the orange juice, lemon juice and honey together. Then you have great soup for use!Then, boil the noodles and add some salt into the water. Put the noodles into cold water.Next, put the noodles in a big bowl! Add the chicken slices, strawberries, green onions and lettuce to the noodles and mix them up. Put the cheese on it.Finally, pour the soup into the noodles.根据短文内容,判断正误,正确的为T,错误的为F。
8年级上册英语第八单元基础检测题
Unit 8基础测试一、选择填空(15小题,每小题1分,共15分)从A、B、C、D四个选项中选出一个最佳答案。
1.—Please spend more time on your lessons from now on.—________. I’ll try my best.A.Yes, I will B.Yes, I do C.No, I don’t D.No, I won’t 2.________ take a bus to go the Palace Museum.A.Let’s B.Let C.What about D.Why don’t 3.To keep healthy, you should eat ________ vegetables and ________ fast food. A.more;less B.more;fewer C.fewer;more D.less;more 4.—Would you please fill the cup ________ some tea and give it to me?—OK. Wait for a few minutes.A.with B.of C.for D.from 5.—What can I do for you, sir?—I’d like ________.A.two bag of salt B.two bags of salt C.two bag of salts D.two bags of salts 6.—What can I do for you, Madam?—I would like some ________ and ________.A.sandwich; sugar B.sandwiches; sugars C.sandwiches; sugar D.sandwich; sugars7.The math problem is too difficult. The students don’t know ________ it.A.how to solve B.what to solve C.when to solve D.why to solve 8.Different people have different hobbies. ________ like reading books, and ________ like drawing pictures.A.Some; the other B.Some; others C.Some; another D.One; the other 9.________ my grandpa is old, he looks very strong and healthy.A.Because B.If C.Although D.When10.________ he was very tired, he kept working in his office.A.Since B.Although C.As soon as D.Because11.—There ________ a wonderful football game this evening. Let’s watch it together. —Sounds great.A.is going to have B.will be C.is D.are 12.—Did you clean your room this morning?—No. But I ________ it at once.A.cleaned B.am cleaning C.will clean D.clean 13.—Can you tell me how to save water?—There are many ways. For example, ________ the water to do some cleaning or water plants after _________ your face.A.reuse; washing B.reusing; wash C.reusing; washing D.reuse; wash 14.________ the tap when brushing teeth can save water.A.Turn on B.Turn off C.Turning on D.Turning off 15.________! I will give you a surprise!A.Support me B.Support I C.To support I D.Supports me 二、完形填空(10小题,每小题1分,共10分)先通读短文,掌握其大意,然后从A、B、C、D四个选项中选出一个可以填入相应空白处的最佳答案。
人教版八年级上册第十一章《三角形》单元测试(附答案)(5)
87654321DCBA八年级数学人教上第11章·三角形单元检测第Ⅰ卷(选择题 共24分)一、选择题:(每小题3分,共24分) 1、下列各组线段,能组成三角形的是( )A 、2 cm ,3 cm ,5 cmB 、5 cm ,6 cm ,10 cmC 、1 cm ,1 cm ,3 cmD 、3 cm ,4 cm ,8 cm2、在一个三角形中,一个外角是其相邻内角的3倍,那么这个外角是( ) A 、150° B 、135° C 、120° D 、100°3、如图4,△ABC 中,AD 为△ABC 的角平分线,BE 为 △ABC 的高,∠C=70°,∠ABC=48°,那么∠3是( ) A 、59° B 、60° C 、56° D 、22° 4、在下列条件中:①∠A+∠B=∠C;②∠A:∠B ∠:∠C=1:2:3;③∠A=90°-∠B;④∠A=∠B=∠C,能确定△ABC 是直角三角形的条件有( )个.A.1B.2C.3D.45、.坐标平面内下列个点中,在坐标轴上的是( ) A.(3,3) B.(-3,0) C.(-1,2) D.(-2,-3)6.将某图中的横坐标都减去2,纵坐标不变,则该图形( ) A. 向上平移2个单位 B. 向下平移2个单位 C. 向右平移2个单位 D. 向左平移2个单位7.点P (x,y )在第三象限,且点P 到x 轴、y 轴的距离分别为5,3,则P 点的坐标为( ) A.(-5,3) B.(3,-5) C.(-3,-5) D.(5,-3)8、如图6,如果AB ∥CD ,那么下面说法错误的是( ) A .∠3=∠7; B .∠2=∠6C 、∠3+∠4+∠5+∠6=1800D 、∠4=∠8第Ⅱ卷(非选择题 共76分)二、填空题:(每小题4分,共32分)9、如图1,△ABC 中,AD ⊥BC ,AE 平分∠BAC , ∠B=70°,∠C=34°,则∠DAE= 度。
2018年秋八年级上(人教版)英语单元检测卷:Unit8
2018年秋八年级上(人教版)英语单元检测卷:Unit8一、单选题1. Thanksgiving is always the fourth Thursday in November.A.in B.on C.at D.for2. Paul made a nice cage _______the little sick bird till it could fly.A.keep B.kept C.keeping D.to keep3. Remember to the lights when you have a room.A.turn on B.turn off C.turn up D.turn down4. —Tom, supper is ready.—I don’t want to eat________ , Mum. I’m not feeling well.A.anything B.everythingC.something D.nothing5. The Changjiang River is _________in the world.A.a longest riverB.the longest riverC.one of the longest riverD.one of the longest rivers6. Tom is in good health, because he often exercises and eats a lot of healthy .A.food B.water C.pear D.carrot7. —There_______some bread on the plate. You can eat it for breakfast.—OK, I will.A.are B.is C.was D.were8. — do you make fruit salad?—First, cut up the apples, bananas and pears. And then ...A.When B.Where C.Why D.How9. “ exercise every day, my son. It’s good for your health. ”Dad often said to him.A.Takes B.Taking C.Take D.To take10. — butter do we need for a sandwich?—Two teaspoons should be enough.A.How many B.How much C.How long D.How far二、完型填空11. ----What’s the weather like today?---- It’s ________ warm ________ yesterday.A .so; thatB .as; asC .not; untilD .too ; to12. We should have ______fast food, ________fresh vegetables and take enough exercise.A .fewer, fewer B .less, more C .fewer, moreD .less, less13. He always looks . Now he’s looking at his new drawing.A .happy; happilyB .happy; happyC .happily; happilyD .happily; happy14. ---- __________ do you play football?---- Once a week.A .How long B .How soon C .How oftenD .How15. —Let’s make tomato and beef noodles.— .A .Sounds good C .That’s right16. Pizza is a kind of popular food. It ______ from Italy. The pizza capital of the world is Naples. The world’s first pizza _____ is still there. It ______in 1830. The best pizza of today has a(n) ______ history. It was first made by a person _____ Raffaele Esposito in the 1880s. This pizza has the same ______ as t he Italian flag. The Italian flag is red, white and ______. The pizza has red tomatoes, white cheese, and green herbs.D .Don’t worryB .You’re welcome三、多任务混合问题There are many different kinds of pizza today. We can ______ chicken pizza, vegetable pizza, etc.in the restaurant. Some pizza has tomatoes, and some pizz a _____ tomatoes. Most pizza is round,______ some isn’t. You can choose any kind you want.【小题1】A .come B .comes C .are D .am 【小题2】A .theater B .club C .train D .restaurant 【小题3】A .opens B .turns on C .opened D .turned on 【小题4】A .long B .short C .excited D .boring 【小题5】A .name B .names C .named D .naming 【小题6】A .colors B .shape C .time D .recipe 【小题7】A .black B .blue C .yellow D .green 【小题8】A .order B .make C .do D .sell 【小题9】A .has B .doesn’t have C .is D .isn’t 【小题10】A .orB .soC .butD .because17.American schools begin in September after the long summer holidays. There are two terms in a school year, the first term is from September to Januar y, and the second is from February to June. Most American children go to public schools.High school students study only four or five subjects at a time. They usually go to the same classes every day, and they have an assignment(课外作业)for every class. After class they have many activities.After high school, many students go to college. They can go to a small one or a large one. They usually have to pay a lot of money for college educatio n (教育). But there are scholarships (奖学金) for good students, and many college students work part time in order to get money for their education.【小题1】How long do American students study in school every year?A .8 monthsB .9 monthsC .10 monthsD .11 months【小题2】High school students take ______ subjects at a time.A .allB .fourC .fiveD .B or C【小题3】______ can get scholarships.A .Many college students B .All the studentsC .Good high school studentsD .Good college students【小题4】Many college students work part time because ______ .A .they have many activitiesB.they have a lot of free timeC.they like doing thingsD.they have to pay a lot of money for their education【小题5】According to the passage, which sentence is Not true?A.American schools have long summer holidays.A.There are two terms in the USA.B.American students don’t do exercises after class.C.They do part time job to get money to pay for their education.四、阅读单选18. A special day in the United States is Thanksgiving Day. It is always on the fourth Thursday of November. Usually, family members and friends get toget her for a big dinner. People sometimes drive their cars a long way for a family reunion. Many people also take Friday off and make it a long weekend holida y, because most Americans do not work on Saturdays or Sundays. Thanksgiving Day began in 1621, the second year after the first English settlers reached t he new world. They did not have enough food. But the American Indians helped the white men and taught them how to farm.In the autumn after the English settlers came to America, they had a good harvest. They were so pleased. They decided to invite their Indian friends to dinne r to thank them for their help. In terms of a family reunion, Thanksgiving Day is even more important than Christmas Day or New Year's Day to most Ameri cans.【小题1】If November 1st is Monday, when is Thanksgiving Day?A.On November 4.B.On November 18.C.On November 25.D.On November 2.【小题2】In the passage the American Indians were very ________.A.common B.famous C.kind D.clever【小题3】When the first English settlers reached America they ________.A.lived with their family happilyB.had a difficult timeC.taught the American Indians how to farmD.brought the American Indians food【小题4】Why did the English settlers invite the American Indians to dinner?A.To thank them for their help.B.To have a long holiday.C.To teach them how to farm.D.To drive a long way for a family reunion.【小题5】We can guess there are more family reunions ________ in America.A.on Thanksgiving Day than on Christmas DayB.on Christmas Day than on Thanksgiving DayC.on New Year's Day than on Thanksgiving DayD.on New Year's Day than on Christmas Day五、根据首字母填空19. 单词拼写【小题1】The rain p__________down for hours yesterday.【小题2】She always likes to a__________some sugar to coffee while drinking it.【小题3】I usually have some p__________of bread and a glass of milk for breakfast.【小题4】The farmer is d__________holes to plant more trees.【小题5】My family and I are going to E__________and France for vacation this summer.【小题6】This girl is from Sichuan. She always puts much p__________into her food.【小题7】Put the oranges into the b__________. After a while you can drink the orange juice.【小题8】How many h__________do we have to get ready for planting the young trees?【小题9】Listen! Students are c__________the New Year in the room, singing and dancing happily.【小题10】The students enjoy s__________the guests from other schools. They are working warm-hearted.六、话题作文20. 书面表达根据所给提示,写出水果沙拉的制作过程,所给提示词必须都用上,60词左右。
人教版八年级数学上册第十一章单元检测(有答案)
人教版八年级上第十一章三角形单元检测(一)一、选择题(本大题共9小题,每小题3分,共27分.在每小题所给的4个选项中,只有一项是符合题目要求的,请将正确答案的代号填在题后括号内)1.以下列各组线段为边,能组成三角形的是().A.2cm,3cm,5cmB.5cm,6cm,10cmC.1cm,1cm,3cmD.3cm,4cm,9cm2.下列说法错误的是().A.锐角三角形的三条高线、三条中线、三条角平分线分别交于一点B.钝角三角形有两条高线在三角形外部C.直角三角形只有一条高线D.任意三角形都有三条高线、三条中线、三条角平分线3.如果多边形的内角和是外角和的k倍,那么这个多边形的边数是().A.k B.2k+1C.2k+2D.2k-24.四边形没有稳定性,当四边形形状改变时,发生变化的是().A.四边形的边长B.四边形的周长C.四边形的某些角的大小D.四边形的内角和5.如图,在△ABC中,D,E分别为BC上两点,且BD=DE=EC,则图中面积相等的三角形有()对.A.4B.5C.6D.76.在下列条件中:①∠A+∠B=∠C,②∠A∶∠B∶∠C=1∶2∶3,③∠A=90°-∠B,④∠A=∠B-∠C中,能确定△ABC是直角三角形的条件有().A.1个B.2个C.3个D.4个7.如果三角形的一个外角小于和它相邻的内角,那么这个三角形为().A.钝角三角形B.锐角三角形C.直角三角形D.以上都不对8.如图,把△ABC纸片沿DE折叠,当点A落在四边形BCDE内部时,∠A与∠1+∠2之间有一种数量关系始终保持不变,请试着找一找这个规律,你发现的规律是().A.∠A=∠1+∠2B.2∠A=∠1+∠2C.3∠A=2∠1+∠2D.3∠A=2(∠1+∠2)9.一个角的两边分别垂直于另一个角的两边,那么这两个角之间的关系是().A.相等B.互补C .相等或互补D .无法确定二、填空题(本大题共9小题,每小题3分,共27分.把答案填在题中横线上)10.造房子时,屋顶常用三角形结构,从数学角度来看,是应用了__________,而活动挂架则用了四边形的__________.11.已知a ,b ,c 是三角形的三边长,化简:|a -b +c |-|a -b -c |=__________.12.等腰三角形的周长为20cm ,一边长为6cm ,则底边长为__________.13.如图,∠ABD 与∠ACE 是△ABC 的两个外角,若∠A =70°,则∠ABD +∠ACE =__________.14.四边形ABCD 的外角之比为1∶2∶3∶4,那么∠A ∶∠B ∶∠C ∶∠D =__________.15.如果一个多边形的内角和等于它的外角和的3倍,那么这个多边形是__________边形.16.如图,∠A +∠B +∠C +∠D +∠E +∠F =__________.17.如图,点D ,B ,C 在同一直线上,∠A =60°,∠C =50°,∠D =25°,则∠1=__________.18.如图,小亮从A 点出发,沿直线前进10米后向左转30°,再沿直线前进10米,又向左转30°,……照这样走下去,他第一次回到出发地A 点时,一共走了__________米.三、解答题(本大题共4小题,共46分)19.(本题满分10分)一个正多边形的一个外角等于它的一个内角的13,这个正多边形是几边形?20.(本题满分12分)如图所示,直线AD 和BC 相交于点O ,AB ∥CD ,∠AOC =95°,∠B =50°,求∠A 和∠D .21.(本题满分12分)如图,经测量,B处在A处的南偏西57°的方向,C处在A处的南偏东15°方向,C处在B处的北偏东82°方向,求∠C的度数.22.(本题满分12分)如图所示,分别在三角形、四边形、五边形的广场各角修建半径为R的扇形草坪(图中阴影部分).(1)图①中草坪的面积为__________;(2)图②中草坪的面积为__________;(3)图③中草坪的面积为__________;(4)如果多边形的边数为n,其余条件不变,那么,你认为草坪的面积为__________.参考答案1.B点拨:只有B中较短两边之和大于第三边,能组成三角形.2.C点拨:直角三角形也有三条高,只是有两条与边重合了,因此C错误,故选C.3.C点拨:任何多边形的外角和都是360°,所以内角和就是180°的2k倍,即(n-2)=2k,所以边数n=2k+2,故选C.4.C点拨:四边形形状改变时,只是改变了四个角的大小,内角和、边长、周长都不改变.故选C.5.A点拨:等底同高的三角形的面积是相等的,所以△ABD,△ADE,△AEC三个三角形的面积相等,有3对,△ABE与△ACD的面积也相等,有1对,所以共有4对三角形面积相等,故选A.6.D点拨:根据三角形内角和定理可知,①中∠C=90°,②中∠C=90°,③中∠A+∠B=90°,两锐角互余,④中∠B=90°,所以①②③④都能判定是直角三角形,故选D.7.A点拨:外角小于内角,它们又互补,所以内角大于90°,故三角形为钝角三角形.故选A.8.B点拨:∠A=180°-(∠B+∠C)=180°-(∠AED+∠ADE),所以∠B+∠C=∠AED+∠ADE,在四边形BCDE中,∠1+∠2=360°-2(180°-∠A),化简得,∠1+∠2=2∠A.9.C点拨:如图,有两种情况,一是∠A与∠D的两边互相垂直,另一种是∠A与∠BDE的两边所在的直线相互垂直,根据四边形内角和是360°,能得到第一种情况时互补,第二种情况时相等,所以两角相等或互补,故选C.10.三角形的稳定性不稳定性11.2a-2b点拨:因为a,b,c是三角形的三边长,三角形两边之和大于第三边,所以a-b+c>0,a-b-c<0,所以原式=a-b+c-[-(a-b-c)]=2a-2b.12.8 cm或6 cm点拨:当腰长是6 cm时,根据周长20 cm求得底边长是8 cm,能组成三角形;当底边长是6 cm时,求得腰长是7 cm,也能组成三角形,两种情况都成立,所以底边长是8 cm或6 cm.13.250°点拨:由∠A=70°,可得∠ABC+∠ACB=110°,∠ABD+∠ACE+∠ABC+∠ACB=360°,所以∠ABD+∠ACE=360°-110°=250°,也可用外角性质求出.14.4∶3∶2∶1点拨:由外角之比是1∶2∶3∶4可求得四边形ABCD的外角分别是36°,72°,108°,144°,内角分别是144°,108°,72°,36°,所以它们的比是4∶3∶2∶1.15.八点拨:由题意可知内角和是360°×3=1 080°,所以是八边形.16.360°点拨:由图可知∠1=∠A+∠B,∠2=∠C+∠D,∠3=∠E+∠F,∠1,∠2,∠3的和是中间的三角形的外角和,等于360°,所以∠A+∠B+∠C+∠D+∠E+∠F=360°.17.45°点拨:在△ABC中,∠ABC=180°-∠A-∠C=70°,∠1=∠ABC-∠D=70°-25°=45°.18.120点拨:由题意可知,回到出发点时,小亮正好转了360°,由此可知所走路线是边长为10米,外角为30°角的正多边形,360°÷30°=12,所以是正十二边形,周长。
(名师整理)数学八年级上册 《第11章 三角形》单元检测试题(含答案解析)
第十一章《三角形》单元测试题一、选择题(每小题只有一个正确答案)1.三角形是()A.由三条线段组成的图形B.由不在同一条直线上的三条线段首尾顺次相接所成的图形C.连接任意三点组成的图形D.以上说法都不对2.如图,已知AB∥CD,若∠A=20°,∠E=35°,则∠C等于()A.20°B.35°C.45°D. 55°3.如图己知DF⊥AB,∠A=35°,∠D=50°,则∠ACB的度数为()A.100°B.105°C.90°D.80°4.如图,在△ABC中,BD平分∠ABC,CD平分∠BCA,若∠D=3∠A,则∠A=()A.32°B.36°C.40°D.44°5.将一副三角板按如图所示摆放,图中∠α的度数是()A.120°B.105°C.90°D.75°6.如图是一个由四根木条钉成的框架,拉动其中两根木条后,它的形状将会改变,若固定其形状,下列有四种加固木条的方法,不能固定形状的是钉在()两点上的木条.A.A、FB.C、EC.C、AD.E、F7.如图,在△ABC中,EF∥AC,BD⊥AC,BD交EF于G,则下面说法中错误的是()A.BD是△BDC的高B.CD是△BCD的高C.EG是△BEF的高D.BE是△BEF的高8.如图,l1∥l2,l3⊥l4,∠1=42°,那么∠2的度数为()A.48°B.42°C.38°D.21°9.一个多边形的每一个外角都是72°,那么这个多边形的内角和为()A.540°B.720°C.900°D.1080°10.具备下列条件的△ABC中,不是直角三角形的是()A.∠A+∠B=∠CB.∠A=∠B=∠CC.∠A:∠B:∠C=1:2:3D.∠A=2∠B=3∠C11.如图,△ABC的角平分线AD,中线BE交于点O,则结论:①AO是△ABE的角平分线;②BO是△ABD的中线.其中()A.①、②都正确B.①、②都不正确C.①正确②不正确D.①不正确,②正确12.一个多边形的内角和比它的外角和的2倍还大180°,这个多边形的边数为()A. 7B. 8C. 9D. 10二、填空题13.如图,按虚线剪去长方形纸片的相邻两个角,并使∠1=150°,AB⊥BC,则∠2=度.14.图1中∠1的度数是;图2中∠1的度数是;图3中∠1的度数是____________.15.某机器零件的横截面如图所示,按要求线段AB和DC的延长线相交成直角才算合格,一工人测得∠A=23°,∠D=31°,∠AED=143°,请你帮他判断该零件是否合格(填“合格”或“不合格”).16.将含30°角的直角三角板的短直角边和含45°角的直角三角板的一条直角边如图放置,则∠1的度数为度.17.按图所示的条件,则∠BAE=度,∠CBD=度.三、解答题18.如图所示,已知AD,AE分别是△ADC和△ABC的高和中线,AB=6cm,AC=8cm,BC=10cm,∠CAB=90°.试求:(1)AD的长;(2)△ABE的面积;(3)△ACE和△ABE的周长的差.19.现有长为57cm的铁丝,要截成n(n>2)小段,每小段的长度为不小于1cm 的整数,如果其中任意3小段都不能拼成三角形,求n的最大值.20.如图,以点A、B、C、D、E中的任意3点为顶点的三角形共有几个,请在图中画出这些三角形.21.如图,四边形ABCD中CD⊥DA,CE平分∠DCB交AD于E,AF平分∠DAB交BC 于F,CE∥FA,求∠B.22.如图,在六边形ABCDEF中,AB⊥AF,BC⊥DC,∠E+∠F=260°,求两外角和∠α+∠β的度数.23.已知凸四边形ABCD中,∠A=∠C=90°.(1)如图1,若DE平分∠ADC,BF 平分∠ABC的邻补角,判断DE与BF位置关系并证明;(2)如图2,若BF、DE 分别平分∠ABC、∠ADC的邻补角,判断DE与BF位置关系并证明.答案解析1.【答案】B【解析】由不在同一条直线上的三条线段首尾顺次相接所组成的图形叫做三角形,所以答案为B.2.【答案】D【解析】∵∠A=20°,∠E=35°,∴∠EFB=∠A+∠E=20°+35°=55°,又∵AB∥CD,∴∠C=∠EFB=55°.故选D.3.【答案】B【解析】∵DF⊥AB,∴∠BFD=90°,又∠D=50°,∴∠B=40°,在△ABC中,根据三角形的内角和定理得:∠ACB=180°-40°-35°=105°.故选B.4.【答案】B【解析】∵∠ABC+∠ACB=180°-∠A,BD平分∠ABC,CD平分∠BCA,∴∠DCB+∠DBC=(∠ABC+∠ACB)=(180°-∠A)=90°-∠A,∴∠D=180°-(∠DCB+∠DBC)=180°-(90°-∠A)=180°-90°+∠A=90°+∠A.∵∠D=3∠A,∴90°+∠A=3∠A,解得∠A=36°.故选B.5.【答案】B【解析】∵图中是一副直角三角板,∴∠BAE=45°,∠E=30°,∴∠AFE=180°-∠BAE-∠E=105°,∴∠α=105°.故选B.6.【答案】D【解析】A.A、F与D能够组三角形,能固定形状;B.C、E与B能够组三角形,能固定形状;C.C、A与B能够组三角形,能固定形状;D.E、F不能与A、B、C、D中的任意点构成三角形,不能固定形状.7.【答案】D【解析】A.BD⊥AC,则BD是△BDC的高,故命题正确;B.CD⊥BD,则CD是△BCD的高,故命题正确;C.EG⊥BG,则EG是△BEF的高,故命题正确;D.错误;8.【答案】A【解析】如图,∵l1∥l2,∠1=42°,∴∠3=∠1=42°,∵l3⊥l4,∴∠2=90°-∠3=48°.故选A.9.【答案】A【解析】∵一个多边形的每一个外角都是72°,多边形的外角和等于360°,∴这个多边形的边数为:360÷72=5,∴这个多边形的内角和为:(5-2)×180°=540°.故选A.10.【答案】D【解析】A.∵∠A+∠B=∠C,∠A+∠B+∠C=180°,∴2∠C=180°,解得∠C=90°,∴△ABC是直角三角形;B.设∠A=x,∠B=2x,∠C=3x,∵∠A+∠B+∠C=180°,∴x+2x+3x=180°,解得x=30°,∴∠C=90°;C.设∠A=x,∠B=2x,∠C=3x,∵∠A+∠B+∠C=180°,∴x+2x+3x=180°,解得x=30°,∴∠C=90°;D.∵∠A+∠B+∠C=180°,而∠A=2∠B=3∠C,∴3∠C+∠C+∠C=180°,解得∠C=,∴∠A=3∠C=.故选D.11.【答案】C【解析】AD是三角形ABC的角平分线,则是∠BAC的角平分线,所以AO是△ABE的角平分线,故①正确;BE是三角形ABC的中线,则E是AC是中点,而O不一定是AD的中点,故②错误.12.【答案】A【解析】设这个多边形的边数为n,根据题意得,(n-2)•180°=360°×2+180°,解得n=7.故选A.13.【答案】120【解析】∠2=90°+180°-∠1=120°.故答案为:120.14.【答案】90°;85°;90°【解析】如图1,∵一个三角形中一个角为30°,另一个角为60°,∴∠1=180°-30°-60°=90°;如图2,∵三角形的外角等于120°,∴∠1=120°-35°=85°;如图3,∵∠1是三角形的外角,∴∠1=45°+45°=90°.故答案为:90°;85°;90°.15.【答案】不合格【解析】延长AB、DC相交F,连接F、E并延长至G.则有(∠A+∠AFG)+(∠D+∠DFG)=∠AEG+∠DEG=∠AED=143°;∵∠A=23°,∠D=31°,∴∠AFD=∠AFG+∠DFG=∠AED-∠A-∠D=143°-23°-31°=89°≠90°.所以零件不合格.16.【答案】75【解析】∵∠2=90°-45°=45°(直角三角形两锐角互余),∴∠3=∠2=45°,∴∠1=∠3+30°=45°+30°=75°.故答案为:75°.17.【答案】138;36【解析】∠BAE=∠ABD+∠ADB=138°,∠CBD=∠ADB-∠C=36°.18.【答案】解:∵∠BAC=90°,AD是边BC上的高,∴AB•AC=BC•AD,∴AD= =6×8 ÷10 =4.8(cm),即AD的长度为4.8cm;(2)∵△ABC是直角三角形,∠BAC=90°,AB=6cm,AC=8cm,∴S△ABC=AB•AC=×6×8=24(cm2).又∵AE是边BC的中线,∴BE=EC,∴BE•AD=EC•AD,即S△ABE=S△AEC,∴S△ABE=S△ABC=12(cm2).∴△ABE的面积是12cm2.(3)∵AE为BC边上的中线,∴BE=CE,∴△ACE的周长-△ABE的周长=AC+AE+CE-(AB+BE+AE)=AC-AB=8-6=2(cm),即△ACE和△ABE的周长的差是2cm.【解析】(1)利用“面积法”来求线段AD的长度;(2)△AEC与△ABE是等底同高的两个三角形,它们的面积相等;(3)由于AE是中线,那么B E=CE,于是△AC E的周长-△ABE的周长=AC+AE+CE-(AB+BE+AE),化简可得△ACE的周长-△ABE的周长=AC-AB,易求其值.19.【答案】8【解析】因为n段之和为定值57cm,故欲n尽可能的大,必须每段的长度尽可能的小.又由于每段的长度不小于1cm,且任意3段都不能拼成三角形,因此这些小段的长度只可能分别是1,1,2,3,5,8,13,21,34,55,但1+1+2+3+5+8+13+21=54<57,1+1+2+3+5+8+13+21+34=88>57,所以n的最大值为8.20.【答案】解:以点A、B、C、D、E中的任意3点为顶点的三角形共有9个,分别是:△ABD,△ABE,△ACD,△ACE,△BCE,△BCD,△DEA,△DEB,△DEC.如图所示:【解析】21.【答案】解:∵CE、AF分别平分∠BCD、∠BAD,∴∠BCD=2∠ECD,∠BAD=2∠FAD,∵AF∥CE,∴∠FAD=∠CED,∵CD⊥DA,∴∠D=90°,∴∠ECD+∠EDC=90°,∴∠BAC+∠BCD=2(∠FAD+∠ECD)=2(∠CED+∠ECD)=2×90°=180°,根据四边形内角和为360°得:∠B=360°-(∠BAD+∠BCD)-∠D=360°-180°-90°=90°.【解析】根据角平分线的性质得到∠BCD=2∠ECD,∠BAD=2∠FAD,根据AF∥CE,得到∠FAD=∠CED,由∠D=90°,从而得到∠ECD+∠EDC=90°,可得∠BAC+∠BCD=2(∠FAD+∠ECD)=180°,再根据四边形内角和为360°,即可解答.22.【答案】解:∵AB⊥AF,BC⊥DC,∴∠A+∠C=180°,∵∠E+∠F=260°,∴∠EDC+∠ABC=(6-2)×180°-90°×2-260°=280°,∴∠α+∠β=360°-(∠EDC+∠ABC)=80°.故两外角和∠α+∠β的度数为80°.【解析】先根据垂直的定义和多边形内角和定理得到∠EDC+∠ABC的度数,再根据多边形内角与外角的关系即可求解.23.【答案】解:(1)DE⊥BF,延长DE交BF于点G∵∠A+∠ABC+∠C+∠ADC=360°又∵∠A=∠C=90°,∴∠ABC+∠ADC=180°∵∠ABC+∠MBC=180°∴∠ADC=∠MBC,∵DE、BF分别平分∠ADC、∠MBC∴∠EDC=∠ADC,∠EBG=∠MBC,∴∠EDC=∠EBG,∵∠EDC+∠DEC+∠C=180°∠EBG+∠BEG+∠EGB=180°又∵∠DEC=∠BEG∴∠EGB=∠C=90∴DE⊥BF;(2)DE∥BF,连接BD,∵DE、BF分别平分∠NDC、∠MBC∴∠EDC=∠NDC,∠FBC=∠MBC,∵∠ADC+∠NDC=180°又∵∠ADC=∠MBC∴∠MBC+∠NDC=180°∴∠EDC+∠FBC=90°,∵∠C=90°∴∠CDB+∠CBD=90°∴∠EDC+∠CDB+∠FBC+∠CBD=180°即∠EDB+∠FBD=180°,∴DE∥BF.【解析】(1)DE⊥BF,延长DE交BF于G.易证∠ADC=∠CBM.可得∠CDE=∠EBF.即可得∠EGB=∠C=90゜,则可证得DE⊥BF;(2)DE∥BF,连接BD,易证∠NDC+∠MBC=180゜,则可得∠EDC+∠CBF=90゜,继而可证得∠EDC+∠CDB+∠CBD+∠FBC=180゜,则可得DE∥BF.。
人教新目标英语八年级上学期单元反馈Unit11单元步步为赢测试试题
⼈教新⽬标英语⼋年级上学期单元反馈Unit11单元步步为赢测试试题【步步为赢】新⽬标英语⼋年级上学期单元反馈第11单元步步为赢卷听⼒部分(共20分)I. 听单词, 从你所听到的A, B, C, D中找出下列句中的斜体单词。
(5分)1. Go and feed the cat, Jill.2. Gary never cleans her room.3. Can you help me do the dishes?4. Let's sweep the yard after lunch.5. Do you put it in the trash basket?1. ________2. ________3. ________4. ________5. ________II. 听句⼦, 根据其内容回答下⾯的问题。
(5分)1. Why does Jenny often help Jill put on her clothes?____________________________________2. Whose dictionary(字典)does Allan want to borrow?____________________________________3. When did Susan do the laundry?____________________________________4. What's Phillip going to do?____________________________________5. What's Grace's brother doing now?____________________________________III. 听短⽂, 根据其内容,写出下列五幅图的顺序。
(10分)笔试部分(共80分)I. 词汇。
(10分)A) 根据句意及所给⾸字母,完成单词。
2022年人教版八年级上册U8单元检测附答案
Unit 8 How do you make a banana milk shake单元测试题一、单项选择1. Careful! Or you will __ the car.A. turnB. turn intoC. turn overD. turn on2. Excuse me. Whose __ is the nextA. isB. turnC. onD. take turn3. Please __ your homework.A. turn inB. make inC. hand inD. interested in4. Would you mind __ the CD The baby is asleep.A. closingB. turning upC. turning downD. turn down5. Let me see the cover of the book if you __ the book.A. turn intoB. take turnsC. turn downD. turn over6. Tom saw a man __ room carefully.A. to walk intoB. entering intoC. walking intoD. to enter7. Do you see JohnNo, but just now, he still __ the room.A. is inB. was inC. intoD. was into8. You had better read the __ before you use the ice-box.A. ingredientB. instructionC. introductionD. structure9. The water in the Yellow river in winter is much __ than in summer.A. littleB. fewerC. lessD. more10. The books on the table is __ than those on that table.A. fewB. lessC. fewerD. most11. A number of animals __ on the earth because of pollution.A. disappearB. appearC. disappearsD. appears12. The number of animals on the earth __ more than 1 million.A. areB. disappearC. appearD. is13. A great deal of __ are canceled .(被取消)A. tradeB. businessC. marketD. deals14. The ground __ when the earthquake happened.A. is shakingB. was shakingC. was movingD. is keeping15. Would you like to pass me __A. two cakesB. two piece of cakeC. two pieces of cakesD. two pieces of cake16. __ is over 1000.A. A number of workersB. the number of workersC. a number17. He told me __ of income.A. amountB. the amountC. an amount二、完形填空完型填空We all know that it is __1__to keep healthy. But not all people know ___2__to keep healthy. Afterfive days' hard work, we need to have a good rest at weekends. But it seems that some don't know how to spend weekends in the right way. They enjoy ___3__ cards at night and don't go to bed until midnight or even later. Some gamble (赌博) all night. They forget that to get___4__sleep is essential (必要的) for health. Some never get up early in the __5___ and take some exercise. It is true that doing exercise is very important for us to keep ___6__.Some smoke a lot. They forget that __7___ smokers are more likely (可能) to have lung cancer (肺癌) than those who don't smoke. Some drink too much wine. ____8___ too much is harmful (有害) to the body. Some eat too much rich food and get fatter and fatter. If you are much too fat, you may always ____9___ tired. Vegetables are good to the body. But some don't like eating vegetables. _____10___ is also very good to body. As a saying (谚语) goes, "An apple every day keeps the doctor away." So don't forget to eat some fruit.( ) 1. A. important B. good C. nice D. happy( ) 2. A. when B. how C. what D. why( ) 3. A. to play B. play C. playing D. plays( ) 4. A. much B. many C. a little D. enough( ) 5. A. morning B. afternoon C. evening D. day( ) 6. A. health B. healthy C. clear D. up( ) 7. A. light B. heavy C. good D. strong( ) 8. A. Drink B. Drinking C. Eat D. Smoke( ) 9. A. are B. keep C. say D. feel( ) 10. A. Water B. Milk C. Tea D. Fruit三、阅读理解1. "You are welcome to have dinner with me on Sunday," said John. "But I don't know where yourhouse is." said Herry."It's easy. You get off the bus. Then you cross the road. You take the first road on the left. You walk for five minutes. Then you come to a big tree. You take the second on the right after the tree. About one hundred meters down this road there is a big red house. You go past the big house, and after about hundred meters, you'll see a small yellow house beside a little tree. Open the door with your foot.""With my foot" said Henry."Why yes," said John, "well, you won't come to my house with empty hands, will you" ( ) 1. From the story we know that John asked Henry _______.A. to go to the cinemaB. to have supper with JimC. to go to the bus stop( ) 2. "You take the first on the left" means _______.A. go ahead on the leftB. take the first bus on the leftC. take the first road on the left.( ) 3. How far is it from the big tree to the big red houseA. about one hundred meters away.B. five minutes' walk.C. about five hundreds feet( ) 4. Where was John's house It was ____.A. on the right after the big houseB. a small yellow houseC. beside a little tree.( ) 5. Why did John asked Henry to open the door with his foot Because Henry _______.A. had no handsB. was afraid to open with his handsC. would carry a lot of things in his hands.2. E-mail: PartyFrom: 11350@ (Lisa Raster)To: Jenny Smith@ yahoo (Jenny Smith)Subject: Party!!!__________________________________________________.Hi Jenny. Listen, I'm having a party this Friday at my house. Just a few friends will be there. Mostly they 're from the office. My boyfriend Tom will also come. He's a nice guy. I want you to meet him.Do you want to come We'll play games and talk. Then we'll eat dinner. Everybody will bring food or drinks. The party is this Friday. It starts at 4:00 PM. It will end at 8 or 9 PM.We'l1 have a great time! Can you come I hope so ! Let me know soon. Call me or send me an e-mail.Lisa( ) 1. "Mostly they're friends from the office." What does "friends from the office" meanA. Lisa's co-workers.B. Living at the company.C. Tom's co--workers.( ) 2. They will eat _______at the party.A. breakfastB. lunchC. dinner( ) 3. Who will not go to the partyA. All of Jenny's friends.B. Somebody's boyfriend.C. Lisa's friends..( ) 4. What is true about the partyA. Many people will go.B. It will last four or five hours.C. It's on the weekend.( ) 5. What will Jenny do firstA.Buy food for the party.B. Call Tom.C. Send an e--mall to Lisa.四、写作请你写一篇制作玉米花(popcorn)的小短文。
人教版英语八年级上册Unit8 单元过关检测(100分)
Unit8 单元过关检测(100分)(时间:45分钟)Ⅰ.单项选择。
(20分)( )1. ---Tom, It’s too dark in the classroom. Please _______the light. ---OK!A. turn onB. turn upC. turn downD. turn off( )2. ---Look ! The banana is too big. Why don’t you _______first? –That sounds a good idea!A. cut up itB. cut it upC. cut up themD. cut them up( )3. ---How ______yogurt would you like to make a salad? ---Only one teaspoon.A. manyB. fewC. muchD. often( )4. How ______your sister _______a milk shake?A. do; makeB. does; makeC. does, makesD. do, makes( )5. ---It’s better for you to _______the pear if you would like to eat.---Why?---Because there is some pesticide (农药) on it..---Oh, I see, thank you.A. pourB. peelC. washD. cook( )6. Please ________the TV. I want to watch football match on TV.A. turn onB. turn offC. openD. close( )7. There’s ________ lettuce in the refrigerator. Go and buy some.A. littleB. a littleC. fewD. a few( )8. Jim is ill. He ______to hospital at once.A. needs go B .need to go C. needs to go D. need go( )9. ---_______cut up one more apple? ---Yes, we do.A. need weB. Do we needC. Do we need toD. Must we( )10. Do you like coffee ________ tea?A. inB. onC. toD. with( )11. If you add one _______two, you’ll get three.A. andB. withC. toD. on( )12. ________ sugar do we need?A. How manyB. How muchC. How longD. How far( )13. It’s time for weather report. Please _________ the TV.A. turn overB. turn onC. turn downD. turn off( )14. ---How do you make the fruit salad? _________.A. Put the pizza in the ovenB. Cut up an apple and a tomatoC. Turn on the blenderD. Mix it all.( )15. You need some help with your math, _________ you?A. aren’tB. needn’tC. don’tD. mustn’t( )16. Please give me a _________ orange.A. bottleB. bottle ofC. full ofD. /( )17. Give me__________.A. two papersB. two paperC. two piece of papersD. two pieces of paper( )18. How many _________ do you need?A. yogurtB. milkC. meatD. oranges.( )19. They put __________ sugar in the coffee.A. a fewB. anyC. someD. many( )20. There are __________ tomatoes for you to eat.A. a little moreB. muchC. lot ofD. some moreⅡ.完形填空。
外研版八年级英语上册-Module 11 点拨训练单元检测卷及答案
Module 11达标测试卷题号一二三四五六七八九十十一十二总分得分第Ⅰ卷听力部分(20分))一、听句子,选择符合句意的图片(每小题1分,共5分)A B CD E1.________ 2.________ 3.________4.________ 5.________二、听对话,选择正确答案(每小题1分,共5分)听第一段材料,回答第67题。
6.What is Jenny doing?A.She is watching a football match on TV.B.She is watching a basketball match on TV.C.She is watching the news on TV.7.Where does the woman want to visit?A.The USA. B.China. C.England.听第二段材料,回答第810题。
8.Why will Tom go to Dalian for the summer holiday?A.Because it's warm in summer.B.Because there are nice beaches in Dalian.C.Because there is a beautiful lake in Dalian.9.What's the weather like in Dalian in summer?A.Hot. B.Rainy. C.Cool.10.How long will it take Tom to get to Dalian by plane?A.About 5 hours. B.About 15 hours.C.About 50 hours.三、听对话,选择正确的答案(每小题1分,共5分)11.When is the Spring Festival?A.Today. B.Tomorrow.C.The day after tomorrow.12.Can people do any cleaning on the first day of the Spring Festival?A.Yes,they can. B.No,they can't.C.No,they needn't.13.Why can't people break anything?A.Because it's too expensive.B.Because it means bad luck.C.Because it means good luck.14.What does Mary like very much?A.Dumplings. B.Papercuts.C.Lanterns.15.What kind of special things can people go to see?A.Lanterns. B.Papercuts.C.The Dragon and Lion Dance.四、听短文,判断正(T)误(F)(每小题1分,共5分)16.The MidAutumn Day is on e of the most important traditional festivals in China.( ) 17.The most popular food on the MidAutumn Day is dumplings.()18.Each family will have the members get together to have a big dinner on that day.( ) 19.On that night,the moon is the brightest.( )20.Some old people would like to tell the children a story about the dragon.( ) 第Ⅱ卷笔试部分(100分)五、单项选择(每小题1分,共15分)21. It's not ________ that Usain Bolt broke the world record again in Berlin.He is so talented.A.surprise B.surprised C.surprising D.surprises22.I am glad to ________ your advice on learning English.A.listen B.lend C.accept D.bring23.—Did you notice someone _______the meeting room just now?—Sorry, I was making a phone call.A.to leave B.leaves C.leave D.left24.—________we clean the classroom immediately?—No, you ________. You ________clean it after school.A.Must; needn't; can B.Need; mustn't; mayC.Must; mustn't; can D.Shall; can't; may25.—The school has decided to give us another day's holiday.—________!A.You can't be serious B.You can be seriousC.You must be serious D.You mustn't be serious26. It's surprising that Mr. Ma's little daughter ________speak English so well.A.must B.can C.mustn't D.can't27.In England people usually drink tea ________ milk.A.in B.at C.with D.on28.—________bad weather! We can't go for a picnic because of the rain today.—I hope it'll stop soon.A.What B.How C.What a D.How a29. I used to(过去常常) ________ with my wife and watch TV at home.A.show up B.wake up C.come up D.stay up30.—Must I return the book today?—No,you ________. You can do it tomorrow.A.can't B.needn't C.mustn't31.—I forgot to bring my dictionary. Could I use yours?—Yes, you ________.A.can B.must C.could D.should32.—Wow! Your drawing is the best of all.—________.A.Just soso B.I think soC.Thank you D.No,it's bad33. 易错题—I like the party so much,but I ________ go home.It's too late.—What a pity!A.have to B.might C.can D.may34. 易错题 ________ they taste ________?A.Do;good B.Does;goodC.Do;well D.Does;well35. 易错题 There is ________ in England.A.something interesting B.interesting somethingC.something interested D.interested something六、完形填空(每小题1分,共10分) (词数:约160;建议用时:6分钟)In China, very few children make pocket money(零花钱). ________(36),in western countries,most kids make pocket money by themselves. They make money in many different ________(37). When kids are very young, their parents help them sell the fruits of their own trees to neighbours(邻居). Kids may also help ________(38) do housework to make money at home. When they ________(39) sixteen, they can make money by sending newspapers or by working in fast food restaurants,________(40) during the summer holidays.There are ________(41) advantages(优点) of making pocket money by kids themselves. First of all, they learn the value(价值) of money by working hard ________(42) they will not waste any. Secondly, they learn to ________(43)money to buy things they need or want, such as books, pencils,movies and even clothes they like. Thirdly, they ________(44)deal with(处理) daily life problems by helping their parents or others. Making pocket money is ________(45) for children when they grow up. That is why parents encourage their kids to make pocket money.36.A.Also B.Or C.However D.Besides37.A.ways B.job C.homes D.countries38.A.teachers B.friendsC.parents D.neighbours39.A.reached B.had C.have D.reach40.A.really B.hardly C.properly D.especially41.A.much B.many C.little D.few42.A.because B.enough C.so D.as soon as43.A.count B.waste C.manage D.change44.A.want to B.give to C.like to D.learn to45.A.helpful B.careful C.beautiful D.useful七、阅读理解(每小题2分,共30分)A (词数:约150;建议用时:6分钟)阅读以上节选自学校国际文化周活动中的海报,根据其内容回答下列各个小题。
2020年人教版英语八年级上册Unit8单元测试卷(含答案)
八年级英语unit8单元检测题一、听力理解(本大题共20小题,每小题1分,满分20分)第一节、听句子,根据句子的内容选择正确的图片回答问题,每段录音听一遍。
( )1.What does Jack often eat for breakfast?( )2.What can the boy make?( )3.How's the weather?( )4.What does Li Hua want to buy?( )5.Where was the girl?第二节、听对话,根据每段对话的内容选择正确答案回答问题。
每段录音听两遍。
听第一段对话,回答第6小题( )6. What did Lily put in the shake?A. Some cheese.B. Some sugar.C. Some honey.听第二段对话,回答第7小题( )7. What’s the girl’s favorite?A. Banana milk shake.B. Apple milk shake.C. Watermelon milk shake. 听第三段对话,回答第8小题( )8. What did Li Hua look for?A. The salt.B. The bottle.C. The sugar.听第四段对话,回答第9小题( )9. What does Peter know how to make?A. Bread.B. Cakes.C. Popcorn.听第五段对话,回答第10小题( )10. What do they need to make the salad?A. Two cups of yogurt.B. Two cups of butter.C. One cup of yogurt. 听第六段对话,回答第11至12小题。
( )11.Where did the woman eat lunch?A. In a school dining hall.B. In a restaurant.C. In a hotel.( )12.What were NOT in the fruit salad?A. Some apples.B. Some strawberries.C. Some pear s.听第七段对话,回答第13至15小题。
2022-2023学年人教版八年级数学上册第11章三角形 单元达标测试题 (word版含答案)
2022-2023学年人教版八年级数学上册《第11章三角形》单元达标测试题(附答案)一.选择题(共8小题,满分40分)1.已知一个三角形的两边长分别为6和3,则这个三角形的第三边长可能是()A.3B.6C.9D.102.一个多边形的每个外角都是45°,则这个多边形的边数为()A.八B.九C.十D.七3.如图,在△ABC中,AF平分∠BAC交BC于点F、BE平分∠ABC交AC于点E,AF与BE相交于点O,AD是BC边上的高,若∠C=50°,BE⊥AC,则∠DAF的度数为()A.10°B.12°C.15°D.20°4.如图,在△CEF中,∠E=78°,∠F=47°,AB∥CF,AD∥CE,连接BC,CD,则∠A的度数是()A.45°B.47°C.55°D.78°5.如图,在△ABC中,∠ABC的平分线与∠ACB的外角平分线相交于D点,∠A=50°,则∠D=()A.15°B.25°C.30°D.45°6.如图,人字梯中间一般会设计一“拉杆”,以增加使用梯子时的安全性,这样做蕴含的道理是()A.三角形具有稳定性B.三角形内角和等于180°C.两点之间线段最短D.同位角相等,两直线平行拉杆7.下列各组图形中,BD是△ABC的高的图形是()A.B.C.D.8.如图,在三角形ABC中,AH⊥BC,BF平分∠ABC,BE⊥BF,EF∥BC,以下四个结论:①AH⊥EF;②∠ABF=∠EFB;③AC∥BE;④∠E=∠ABE.其中正确的结论有()A.4个B.3个C.2个D.1个二.填空题(共8小题,满分40分)9.已知三角形的两边a和b的长分别为3和8,则第三边c的范围为.10.若一个正多边形的内角和与它的外角和之和是1260°,则这个正多边形的边数是.11.如图,在△ABC中,AD⊥BC,CE⊥AB,且AD与CE交于点H,若∠B=50°,则∠AHC的度数为°.12.如图,△ABC中,∠B=40°,∠C=30°,点D为边BC上一点,将△ADC沿直线AD 折叠后,点C落到点E处,若∠BAE=50°,则∠DAC的度数为°.13.如图,在△ABC中,AD是BC边上的高,AE是∠BAC的平分线,若∠B=70°,∠C =40°,则∠DAE的度数为.14.在锐角△ABC中,将∠a的顶点P放置在BC边上,使∠a的两边分别与边AB,AC交于点E,F(点E不与B点重合,点F不与点C重合,且点E,F均不与点A重合).(1)当∠BAC=40°,∠a=60°时,∠BEP+∠CFP=°;(2)直接写出∠BEP,∠CFP,∠BAC,∠a之间的数量关系.15.在△ABC中,AB<AC,BC边上的中线AD将△ABC分成的两个新三角形的周长差为5cm,AB与AC的和为13cm,则AC的长为.16.如图,在△ABC中,∠C=90°,BE平分∠ABC,AF平分外角∠BAD,BE与F A交于点E,则∠E的度数为.三.解答题(共5小题,满分40分)17.如图所示,在△ABC中,AD平分∠BAC交BC于点D,BE平分∠ABC交AD于点E.(1)若∠C=60°,∠BAC=80°,求∠ADB的度数;(2)若∠BED=60°,求∠C的度数.18.如图,在四边形ABCD中,∠D+∠ABC=180°,BE平分∠ABC交CD于点E,连接.(1)若∠C=∠1,求证:∠CBE=∠AED.(2)若∠C=80°,∠D=124°,求∠CEB的度数.19.如图,在△ABC中,E、G分别是AB、AC上的点,F、D是BC上的点,连接EF、AD、DG,AD∥EF,∠1+∠2=180°.(1)说明:AB∥DG;(2)若DG是∠ADC的平分线,∠2=3∠B+40°,求∠B的度数.20.在三角形ABC中,点D在线段AC上,DE∥BC交AB于点E,点F在线段AB上(点F不与点A,E,B重合),连接DF,过点F作FG⊥FD交射线CB于点G.(1)如图1,点F在线段BE上.①用等式表示∠EDF与∠BGF的数量关系,并说明理由;②如图,求证:∠ABC+∠BFG﹣∠EDF=90°;(2)当点F在线段AE上时,依题意,在图2中补全图形,请直接用等式表示∠EDF与∠BGF的数量关系,不需证明.21.在△ABC中,(1)如图1,BP、CP为∠ABC和∠ACB的角平分线,求∠P与∠A之间的关系?(2)如图2,BP、CP为∠ABC和∠ACE的角平分线,求∠P与∠A之间的关系?(3)如图3,BP、CP为∠CBD和∠BCE的角平分线,求∠P与∠A之间的关系?(请选择其中一道小题写出详细过程)参考答案一.选择题(共8小题,满分40分)1.解:根据三角形的三边关系得,第三边长应大于6﹣3=3,而小于6+3=9,答案中,只有B符合题意.故选:B.2.解:∵360÷45=8(边),∴多边形的边数为八,故选:A.3.解:∵BE⊥AC,BE平分∠ABC,∴∠AEB=∠CEB=90°,∠ABE=∠CBE,∵BE=BE,∴△ABE≌△CBE(ASA),∴∠BAC=∠C=50°,∴∠ABC=190°﹣∠BAC﹣∠C=80°,∵AF平分∠BAC,∴∠BAF=∠BAC=25°,∵BE⊥AC,∴∠ADB=90°,∴∠BAD=10°∴∠DAF=∠BAF﹣∠DAB=15°,故选:C.4.解:延长EC交AB于点H,如图所示:∵∠E=78°,∠F=47°,∴∠ECF=180°﹣∠E﹣∠F=55°,∵AB∥CF,AD∥CE,∴∠BHE=∠ECF=55°,∠BHE=∠A,∴∠A=55°.故选:C.5.解:∵∠ABC的平分线与∠ACB的外角平分线相交于D点,∴∠DCE=∠ACE,∠DBC=∠ABC,又∵∠D=∠DCE﹣∠DBC,∠A=∠ACE﹣∠ABC,∴∠D=∠A=25°.故选:B.6.解:人字梯中间一般会设计一“拉杆”,以增加使用梯子时的安全性,这样做的道理是三角形具有稳定性.故选:A.7.解:根据三角形高的定义可知,只有选项B中的线段BD是△ABC的高,故选:B.8.解:∵AH⊥BC,EF∥BC,∴AH⊥EF,故①正确;∵BF平分∠ABC,∴∠ABF=∠CBF,∵EF∥BC,∴∠EFB=∠CBF,∴∠ABF=∠EFB,故②正确;∵BE⊥BF,而AC与BF不一定垂直,∴BE∥AC不一定成立,故③错误;∵BE⊥BF,∴∠E和∠EFB互余,∠ABE和∠ABF互余,而∠EFB=∠ABF,∴∠E=∠ABE,故④正确.故选:B.二.填空题(共8小题,满分40分)9.解:由题意可得8﹣3<c<8+3,∴5<c<11.故答案为:5<c<11.10.解:设正多边形的边数为n,则180×(n﹣2)+360°=1260°,∴n=7,∴这个正多边形的边数是七.故答案为:七.11.解:∵∠B=50°,∠CEB=∠ADB﹣90°,∴∠EHD=180°﹣50°=130°,又∵∠EHD=∠AHC,∴∠AHC=130°,故答案为:130.12.解:∵∠B=40°,∠C=30°,∴∠BAC=110°,∵∠BAE=50°,∴∠CAE=60°,∵△ADC沿直线AD折叠得到△ADE,∴∠CAD=∠EAD=30°,故答案为:30.13.解:∵∠B=70°,∠C=40°,∴∠BAC=70°,∵AD是BC边上的高,∴∠CAD=50°,∵AE是∠BAC的平分线,∴∠CAE=∠BAC=35°,∴∠DAE=∠CAD﹣∠CAE=15°.故答案为:15°.14.解:(1)如图,连接AP,∵∠BEP=∠EAP+∠EP A,∠CFP=∠F AP+∠FP A,∴∠BEP+∠CFP=∠EAP+∠EP A+∠F AP+∠FP A,即∠BEP+∠CFP=∠BAC+∠EPF,∴∠BEP+∠CFP=∠BAC+∠α=40°+60°=100°,故答案为:100°;(2)∠BEP+∠CFP=∠BAC+∠α,理由如下:∵∠BEP=∠EAP+∠EP A,∠CFP=∠F AP+∠FP A,∴∠BEP+∠CFP=∠EAP+∠EP A+∠F AP+∠FP A,即∠BEP+∠CFP=∠BAC+∠EPF,∴∠BEP+∠CFP=∠BAC+∠α.15.解:∵AD是△ABC的中线,∴BD=CD,∵AB<AC,两个新三角形的周长差为5cm,∴(AC+AD+CD)﹣(AB+AD+BD)=5cm,∴AC﹣AB=5cm,∵AB+AC=13cm,∴AC=9cm,故答案为:9cm.16.解:∵BE平分∠ABC,∴∠ABE=.∵AF平分外角∠BAD,∴∠F AB=.又∵∠BAD=∠C+∠ABC=90°+∠ABC,∴∠F AB=.又∵∠F AB=∠E+∠ABE,∴∠E=∠F AB﹣∠ABE=45°+﹣=45°.故答案为:45°.三.解答题(共5小题,满分40分)17.解:(1)∵AD平分∠BAC,∠BAC=80°,∴∠DAC=∠BAC=40°,∵∠ADB是△ADC的外角,∠C=60°,∴∠ADB=∠C+∠DAC=100°;(2)∵∠BED是△ABE的外角,∠BED=60°,∴∠BAD+∠ABE=∠BED=60°,∵AD平分∠BAC,BE平分∠ABC,∴∠BAC=2∠BAD,∠ABC=2∠ABE,∴∠BAC+∠ABC=2(∠BAD+∠ABE)=120°,∵∠BAC+∠ABC+∠C=180°,∴∠C=180°﹣(∠BAC+∠ABC)=60°.18.(1)证明:∵∠C+∠CBE+∠CEB=180°,∠AED+∠1+∠CEB=180°,∠C=∠1,∴∠CBE=∠AED;(2)解:∵∠D+∠ABC=180°,∠D=124°,∴∠ABC=56°,∵BE平分∠ABC,∴∠CBE=∠ABC=28°,∵∠C+∠CBE+∠CEB=180°,∠C=80°,∴∠CEB=72°.19.证明:(1)由题意可知,∠BEF=∠1,∠BFE=∠ADB,∴∠BEF+∠BFE=∠1+ADB,∴180°﹣(∠BEF+∠BFE)=180°﹣(∠1+ADB),即∠B=∠GDC,∴AB∥DG.解:(2)∵DG是∠ADC的平分线,且AB∥DG,∴∠1=∠DGC=∠B,∵∠2=3∠B+40°,∴180°﹣∠1=3∠B+40°,∴180°﹣∠B=3∠B+40°,∴∠B=35°.20.(1)①解:结论:∠EDF+∠BGF=90°.理由:如图1中,过点F作FH∥BC交AC于点H.∵ED∥BC,∴ED∥FH.∴∠EDF=∠1.∵FH∥BC,∴∠BGF=∠2.∵FG⊥FD,∴∠DFG=90°.∴∠1+∠2=90°.∴∠EDF+∠BGF=90°.②证明:过点F作FH∥BC交AC于点H.如图2,∴∠ABC=∠AFH.∴∠ABC=∠1+∠3.∴∠3=∠ABC﹣∠1.∵∠EDF=∠1,∴∠3=∠ABC﹣∠EDF.∵FG⊥FD,∴∠DFG=90°.∴∠BFG+∠3=90°.∴∠3=90°﹣∠BFG.∴90°﹣∠BFG=∠ABC﹣∠EDF.∴∠ABC+∠BFG﹣∠EDF=90°.(2)解:结论:∠BGF﹣∠EDF=90°.理由:设DE交FG于J.如图3,∵DE∥BC,∴∠BGF=∠FJE,∵∠FJE=∠DEJ+∠EDF,∠DEJ=90°,∴∠BGF﹣∠EDF=90°.当点G在CB的延长线上时,同法可证∠EDF+∠BGF=90°,如图3,21.解:(1)∵BP、CP为∠ABC和∠ACB的角平分线,∴∠CBP=,∠BCP=.∴∠CBP+∠CBP=.∵∠A+∠ABC+∠ACB=180°,∴∠ABC+∠ACB=180°﹣∠A.∴∠PBC+∠PCB=.∴∠P=180°﹣(∠PBC+∠PCB)=180°﹣=90°+.(2)∵∠P+∠PBC=∠PCD,∴∠P=∠PCD﹣∠PBC.∵BP、CP为∠ABC和∠ACE的角平分线,∴∠PCD=,∠PBC=.∴∠P==.(3)∵∠DBC=∠A+∠ACB,∠BCE=∠A+∠ABC,∴∠DBC+∠BCE=∠A+∠ACB+∠A+∠ABC=180°+∠A.∵BP、CP为∠CBD和∠BCE的角平分线,∴∠CBP=,∠BCP=.∴=.∴∠P=180°﹣(∠CBP+∠BCP)=180°﹣=90°﹣.。
八年级英语上册第八单元检测题
八年级上册英语第八单元检测题一、单项选择。
( ) 1、What did you ________ yesterday?A. buyB. boughtC. buysD. buying( ) 2、She went ________ a drive after work last Friday?A. to B . for C. in D. by( ) 3、There _______ lots of popcorn in the kitchen last night.A. wereB. hadC. areD. was( ) 4、Do you have ________ to say about this?A. something elseB. anything elseC. else somethingD. else anything( )5、Gina hang out with her friends _________ .A. last SundayB. on SundayC. every SundayD. next Sunday( ) 6、—Did your parents sleep late on weekends? —________.A. Yes, they did.B. No, they don’t.C. Yes, they were.D. No, they weren’t.( ) 7、________ the class, the students left the classroom one by one.A. At the end ofB. In the endC. By the endD. At the end( ) 8、Did you visit my school ________ there was a big library.A. howB. whatC. whereD. when( ) 9、Which of the following is not the city of the USA?A. New YorkB. HawaiiC. San FranciscoD. Chicago( ) 10、—What do you think of sleeping outdoor at night? —________. I like it.A. That sounds terrible.B. It’s awful.C. It sounds exciting.D. Goodidea.( ) 11、Ted cleaned the room on his day _________.A. ofB. offC. downD. away( ) 12、This morning she came to school __________ than usual.A. lateB. laterC. latestD. latter( ) 13、What about going _________ with us?A. fishB. fishesC. fishedD. fishing( ) 14、He had to help his parents __________ on the farm on weekends.A. workB. workingC. worksD. worked( ) 15、What __________ the matter with your little dog yesterday evening?A. isB. wasC. areD. were二、完形填空I think the best place to go on Sunday is the zoo. When you are __51__, you can gothere with your family. __52__ the zoo, there are many animals: elephants, deer,__53__, rabbits and other animals. Elephants are the __54__ animals on land. I __55__ there is a baby elephant in our zoo. So I want to __56__at it. Yu Xuan wantsto go with me. She says, " __57__we go there together?" "Sure!" I say. "We can __58__ a good time there. But let's __59__ there at half past four. I have __60__ homework to do."() 1. A. busy B. free C. young D. clean() 2. A. In B. On C. For D. Near()3. A. monkeys B. monkey C. two monkey D. one monkeys()4. A. youngest B. smallest C. biggest D. tallest() 5. A. listen B. listen to C. hear of D. hear() 6. A. looks B. have a look C. see D. have a see()7. A. Can B. Could C. Shall D. Would()8. A. get B. have C. be D. has()9. A. goes B. go C. to go D. going()10. A. few B. little C. much D. many三、阅读理解(A)I had a summer camp with my classmates last year. Early in the morning. We gathered at the bus station. After saying goodbye to our parents,we got on the buses. Ittook us more than two hours to arrive at the campground. We got off the busescheerfully. Laughing and shouting. We j umped and ran all over the place. It was the first time for us to be away from the parents .Some of us started to feel homesick(想家). However, when the night party and dances began, the homesickness was gone. The next day, everybody rushed to the boating class, hoping to be at the head of theothers. At first ,my friends and I worked hard, but the boat wouldn’t listen tous and kept going round and round. Then the teacher taught us how to work together. After many tries, we did much better. Swimming class was my favorite. It was aboutthe hottest time of a day and the best time to stay in the cool water. The swimmingteacher was a funny man, and during the class he often made u s laugh happily. During the week I learned a lot of new things and made many new friends. I also learnedhow to take care of myself.( ) 1. They got to the campground__________ .A. on footB. by bikeC. by busD. by plane( ) 2. The campground was __________ from their homes.A. quite nearB. not farC. very longD. quite far( ) 3.Why swimming class was the writer’s favorite?A. Because it was good to stay in the cool water when the weather was hot.B. Because the writer felt quite relaxed during the class.C. Because the swimming teacher was interesting.D .Because of all the above()4.Which statement is NOT true?A. he children were happy to be away from Dad and Mum.B. Their homesickness lasted for long.C ..It was teamwork to boat.D. They camped for a week.( )5.Which is the best title for the passage?A. I Learnt a lot.B. Boating and Swimming.C. On the CampgroundD. My First Summer Camp(B).阅读短文,判断正(A)误(B)Len was thirty years old, and he had very long hair, He lived in a big city, butone year he did not find any work there, so he went to a small town and began looking for work there. He went to a lot of places, but nobody wanted him. Then he met anold friend, and this man said to him, “People in this town don’t like long hair.Why don’t you go to a barber (理发师) ? He can cut a lot of it off and then youcan get some work..” Len went to a barber and said, “Please cut most of my hair off.” The barber began. He cut and cut for a long time and then he said to Len ,“Were you in the army a few years ago?”“Yes, I was.” Len answered. “Why did you ask that?”“Because I have found your cap,” the barber answered.( )6. Len was twenty years old.( )7. Len had very long hair.( )8. Nobody wanted Len for work.( )9. Len met an old classmate.( )10. The b arber cut off a lot of Len’s hair.四、词汇运用。
人教版八年级数学上册检测题 第十一章单元检测题
第十一章单元检测题时间:100分钟满分:12022一、选择题(每小题3分,共30分)1.(徐州中考)下列长度的三条线段,能组成三角形的是(D)A.2,2,4 B.5,6,12 C.5,7,2 D.6,8,102.下列事例应用了三角形稳定性的有(B)①人们通常会在栅栏门上斜着钉上一根木条;②新植的树木,常用一些粗木与之成角度地支撑起来防止倒斜;③四边形模具.A.1个B.2个C.3个D.0个3.(杭州中考)在△ABC中,若一个内角等于另外两个内角的差,则(D)A.必有一个内角等于30°B.必有一个内角等于45°C.必有一个内角等于60°D.必有一个内角等于90°4.(赤峰中考)如图,点D在BC的延长线上,DE⊥AB于点E,交AC于点F.若∠A =35°,∠D=15°,则∠ACB的度数为(B)A.65°B.70°C.75°D.85°第4题图第5题图第8题图第9题图第10题图5.(2020·广安)如图,在五边形ABCDE中,若去掉一个30°的角后得到一个六边形BCDEMN,则∠1+∠2的度数为(A)A.210°B.110°C.150°D.100°6.(2020·黄冈)已知一个正多边形的一个外角为36°,则这个正多边形的边数是(D) A.7 B.8 C.9 D.107.多边形每一个内角都等于150°,则从该多边形一个顶点出发,可引出对角线的条数为(C)A.7条B.8条C.9条D.10条8.(2020·湖北)将一副三角尺按如图摆放,点E在AC上,点D在BC的延长线上,EF ∥BC,∠B=∠EDF=90°,∠A=45°,∠F=60°,则∠CED的度数是(A) A.15°B.20°C.25°D.30°9.(2020·宜昌)游戏中有数学智慧,找起点游戏规定:从起点走五段相等直路之后回到起点,要求每走完一段直路后向右边偏行,成功的招数不止一招,可助我们成功的一招是(A)A.每走完一段直路后沿向右偏72°方向行走B.每段直路要短C.每走完一段直路后沿向右偏108°方向行走D.每段直路要长10.如图,把一把直尺放置在一个三角形纸片上,则下列结论正确的是(D)A.∠1+∠6>180°B.∠2+∠5<180°C.∠3+∠4<180°D.∠3+∠7>180°二、填空题(每小题3分,共24分)11.一个起重架的结构如图所示,如果∠1=155°,那么∠2=__65°__.第11题图第14题图第16题图第18题图12.(2020·长春)正五边形的一个外角的大小为__72__度.13.已知△ABC的两条边的长度分别为3 cm,6 cm,若△ABC的周长为偶数,则第三边的长度是__5或7__cm.14.(2020·巴中)如图,是中国象棋残局图的一部分,请用线段将图中棋子所在的格点按指定方向顺次连接,组成一个多边形.连接顺序为:将→象→炮→兵→马→車→将,则组成的多边形的内角和为__720__度.15.在活动课上,小红有两根长为4 cm,8 cm的小棒,现打算拼一个等腰三角形,则小红应取的第三根小木棒的长度是__8__cm.16.如图,AD是△ABC的角平分线,BE是△ABC的高,∠BAC=40°,则∠AFE 的度数为__70°__.17.(哈尔滨中考)在△ABC中,∠A=50°,∠B=30°,点D在AB边上,连接CD,若△ACD为直角三角形,则∠BCD的度数为__60°或10°__.18.如图,∠1+∠2+∠3+∠4+∠5+∠6+∠7=__540°__.三、解答题(共66分)19.(6分)在△ABC中,已知∠A=105°,∠B比∠C大15°,求∠B,∠C的度数.解:∠B=45°,∠C=30°20.(6分)如图,已知AC⊥BC,CD⊥AD,∠B=30°,∠ACD=40°,求图中能用字母表示出来的四边形ABCD的外角的度数.解:图中四边形ABCD的外角有∠CDF,∠BAE,∠CDF=90°,∠BAE=70°21.(6分)(宜昌中考)如图,在Rt △ABC 中,∠ACB =90°,∠A =40°,△ABC 的外角∠CBD 的平分线BE 交AC 的延长线于点E .(1)求∠CBE 的度数;(2)过点D 作DF ∥BE ,交AC 的延长线于点F ,求∠F 的度数.解:(1)∵在Rt △ABC 中,∠ACB =90°,∠A =40°,∴∠ABC =90°-∠A =50°,∴∠CBD =130°.∵BE 是∠CBD 的平分线,∴∠CBE =12∠CBD =65° (2)∵∠ACB =90°,∠CBE =65°,∴∠CEB =90°-65°=25°.∵DF ∥BE ,∴∠F =∠CEB =25°22.(8分)已知a ,b ,c 分别为△ABC 的三边,且满足a +b =3c -2,a -b =2c -6.(1)求c 的取值范围;(2)若△ABC 的周长为18,求c 的值.解:(1)联立⎩⎪⎨⎪⎧a +b =3c -2,a -b =2c -6, 解得⎩⎨⎧a =52c -4,b =12c +2. ∵a ,b ,c 分别为△ABC 的三边,∴⎩⎪⎨⎪⎧a +b >c ,a +c >b ,b +c >a .解得2<c <6.故c 的取值范围为2<c <6 (2)∵△ABC 的周长为18,a +b =3c -2,∴a +b +c =4c -2=18,解得c =5.故c 的值是523.(8分)如图,在△ABC 中,AD 平分∠BAC ,P 为线段AD 上一个动点,PE ⊥AD 交直线BC 于点E .(1)若∠B =35°,∠ACB =85°,求∠E 的度数;(2)当P 点在线段AD 上运动时,猜想∠E 与∠B ,∠ACB 的数量关系,并说明理由.解:(1)在△ABC 中,∵∠B =35°,∠ACB =85°,∴∠BAC =60°,∵AD 平分∠BAC ,∴∠BAD =12∠BAC =30°,∴∠ADC =∠B +∠BAD =65°,∵EP ⊥AD ,∴∠E =90°-∠ADC =25° (2)∠E =12 (∠ACB -∠B ).理由:∵∠ADE =∠B +12∠BAC ,而∠E +∠ADE =90°,∴∠B +12∠BAC +∠E =90°,∠BAC =180°-(∠ACB +∠B ),∴∠B +12 [180°-(∠ACB +∠B )]+∠E =90°,∴∠E =12(∠ACB -∠B ) 24.(10分)在四边形ABCD 中,∠A =∠C =90°.(1)求证:∠ABC +∠ADC =180°;(2)如图①,若DE 平分∠ADC, BF 平分∠CBM ,写出DE 与BF 的位置关系,并证明;(3)如图②,若BF ,DE 分别平分∠ABC ,∠ADC 的外角,写出BF 与DE 的位置关系,并证明.解:(1)∵∠A +∠C +∠ABC +∠ADC =360°,而∠A =∠C =90°,∴∠ABC +∠ADC =180° (2)DE ⊥BF .证明:延长DE 交BF 于点G ,易证∠ADC =∠CBM ,∴∠CDE =∠EBF ,∴∠EGB =∠C =90°,∴DE ⊥BF (3)DE ∥BF .证明:连接BD ,易证∠NDC +∠MBC =180°,∴∠EDC +∠CBF =90°,∴∠EDC +∠CDB +∠CBD +∠FBC =180°,∴DE ∥BF25.(10分)取一副三角板按图①拼接,固定三角板ADC ,将三角板ABC 绕点A 按顺时针方向旋转得到△ABC ′(如图②),设∠CAC ′=α(0°<α<45°).(1)当α=15°时,求证:AB ∥CD ;(2)连接BD ,当0°<α≤45°时,∠DBC ′+∠CAC ′+∠BDC 的度数是否变化?若变化,求出变化范围;若不变,求出其度数.解:(1)∵∠CAC ′=15°,∴∠BAC =∠BAC ′-∠CAC ′=45°-15°=30°,又∠C =30°,∴∠BAC =∠C ,∴AB ∥CD (2)∠DBC ′+∠CAC ′+∠BDC 的度数不变.由图可知A ,B ,C ,C ′,D 构成一个不规则的五角星,易证五角星的内角和等于180°,那么∠DBC ′+∠CAC′+∠BDC+∠C′+∠C=180°,又∠C′=45°,∠C=30°,∴∠DBC′+∠CAC′+∠BDC=180°-45°-30°=105°26.(12分)已知∠MON=40°,OE平分∠MON,点A,B,C分别是射线OM,OE,ON上的动点(点A,B,C不与点O重合),连接AC交射线OE于点D.设∠OAC=x°.(1)如图①,若AB∥ON,则:①∠ABO的度数是__20°__;②当∠BAD=∠ABD时,x=__120__;当∠BAD=∠BDA时,x=__60__;(2)如图②,若AB⊥OM,则是否存在这样的x值,使得△ADB中有两个相等的角?若存在,求出x的若不存在,说明理由.解:(2)分两种情况讨论:①当点D在线段OB上时,若∠BAD=∠ABD,则x=20;若∠BAD=∠BDA,则x=35;若∠ADB=∠ABD.则x=50.②当点D在射线BE上时,∵∠ABE=110°,且三角形的内角和为180°,∴只有∠BAD=∠BDA=35°.∴x=125.综上可知,当x=20,35,50或125时,△ADB中有两个相等的角。
2020年人教版八年级上册第11章《三角形》单元检测卷 含答案
2020年人教版八年级上册第11章《三角形》单元检测卷满分120分一.选择题(共10小题,满分30分,每小题3分)1.要组成一个三角形,三条线段的长度可以是()A.1,2,3B.3,4,5C.4,6,11D.1.5,2.5,4.52.如图,在△ABC中,AB边上的高是()A.CE B.AD C.CF D.AB3.若三角形的三条高的交点在这个三角形的内部,那么这个三角形是()A.锐角三角形B.直角三角形C.钝角三角形D.等边三角形4.已知在△ABC中,∠ACB=90°,∠B=55°,则∠A的度数是()A.25°B.35°C.45°D.65°5.在△ABC中,∠A:∠B:∠C=3:4:8,则这个三角形一定是()A.等腰三角形B.直角三角形C.锐角三角形D.钝角三角形6.如图,小峰从点O出发,前进5m后向右转45°,再前进5m后又向右转45°,…,这样一直走下去,他第一次回到出发点O时,一共走的路程是()A.10米B.20 米C.40 米D.80米7.如图所示的四边形中,若去掉一个50°的角得到一个五边形,则∠1+∠2等于()A.230°B.240°C.250°D.260°8.如图,BD,CD分别是内角∠ABC和外角∠ACE的平分线,若∠A=70°,则∠D=()A.30°B.35°C.40°D.45°9.在△ABC中,∠A=150°.第一步:在△ABC上方确定一点A1,使∠A1BA=∠ABC,∠A1CA=∠ACB,如图1.第二步:在△A1BC上方确定一点A2,使∠A2BA1=∠A1BA,∠A2CA1=∠A1CA,如图2.照此下去,至多能进行()步.A.3B.4C.5D.610.一个多边形截去一角后,变成一个八边形则这个多边形原来的边数是()A.8或9B.7或8C.7或8或9D.8或9或10二.填空题(共8小题,满分24分,每小题3分)11.如图,在建筑工地上,工人师傅砌门时,常用木条EF固定长方形门框,使其不变形,这种做法的根据是.12.在下列条件中:①∠A+∠B=∠C,②∠A:∠B:∠C=1:2:3,③∠A=90°﹣∠B,④∠A=∠B=∠C中,能确定△ABC是直角三角形的条件有(填序号)13.已知一个多边形的内角和是1620°,则这个多边形是边形.14.如图,在△ABC中,点D是BC延长线上一点,∠B=40°,∠ACD=120°,则∠A 的余角是.15.若一个三角形的三边长分别是xcm、(x+5)cm、(13﹣x)cm,则x的取值范围是.16.如图,∠1=∠2,∠3=∠4,∠A=100°,则∠BOC=.17.如图所示,∠A=10°,∠ABC=90°,∠ACB=∠DCE,∠ADE=∠EDF,∠CED=∠FEG.则∠F=.18.如图,则∠A+∠B+∠C+∠D+∠E+∠F的度数为.三.解答题(共9小题,满分66分)19.(6分)求下列图形中x的值:20.(6分)证明:三角形三个内角的和等于180°.已知:△ABC(如图).求证:∠A+∠B+∠C=180°.21.(6分)如图,CE是△ABC的外角∠ACD的平分线,且CE交BA的延长线于点E,若∠B=30°,∠BAC=80°,求∠E的度数.22.(6分)△ABC中,AD是高,AE、BF是角平分线,且相交于点O,∠BAC=60°,∠C=80°,求∠DAE,∠BOA的度数.23.(7分)如图,在△ABC中,∠B=42°,∠C=78°,AD平分∠BAC.(1)求∠ADC的度数;(2)在图中画出BC边上的高AE,并求∠DAE的度数.24.(8分)a,b,c分别为△ABC的三边,且满足a+b=3c﹣2,a﹣b=2c﹣6.(1)求c的取值范围;(2)若△ABC的周长为18,求c的值.25.(8分)如图,已知在△ABC中,∠B与∠C的平分线交于点P.(1)当∠A=70°时,求∠BPC的度数;(2)当∠A=112°时,求∠BPC的度数;(3)当∠A=α时,求∠BPC的度数.26.(9分)(1)如图1,AD平分∠BAC,AE⊥BC,∠B=30°,∠C=70°.①∠BAC=°,∠DAE=°;②如图2.若把“AE⊥BC”变成“点F在AD的延长线上,FE⊥BC”,其它条件不变,求∠DFE的度数;(2)如图3,AD平分∠BAC,AE平分∠BEC,∠C﹣∠B=40°,求∠DAE的度数.27.(10分)如图,∠CBF、∠ACG是△ABC的外角,∠ACG的平分线所在的直线分别与∠ABC、∠CBF的平分线BD、BE交于点D、E.(1)求∠DBE的度数;(2)若∠A=70°,求∠D的度数;(3)若∠A=a,则∠D=,∠E=(用含a的式子表示)参考答案一.选择题(共10小题,满分30分,每小题3分)1.解:根据三角形的三边关系,得A、1+2=3,不能组成三角形;B、3+4>5,能组成三角形;C、4+6<11,不能组成三角形;D、1.5+2.5<4.5,不能够组成三角形.故选:B.2.解:过点C作AB的垂线段CE,则CE为AB边上的高,故选:A.3.解:若三角形的三条高的交点在这个三角形的内部,那么这个三角形是锐角三角形.故选:A.4.解:∵在△ABC中,∠ACB=90°,∠B=55°,∴∠A=180°﹣∠B﹣∠C=180°﹣55°﹣90°=35°,故选:B.5.解:∵∠A:∠B:∠C=3:4:8,∴设∠A=3α,∠B=4α,∠C=8α,∵∠A+∠B+∠C=180°,∴3α+4α+8α=180°,∴α=12°,∴∠C=8α=96°,∴这个三角形一定是钝角三角形,故选:D.6.解:依题意可知,小峰所走路径为正多边形,设这个正多边形的边数为n,则45n=360,解得n=8,∴他第一次回到出发点O时一共走了:5×8=40米,故选:C.7.解:∵∠1=∠A+∠ACB,∠2=∠A+∠ABC,∠A+∠ABC+∠ACB=180°,∴∠1+∠2=∠A+∠ACB+∠A+∠ABC=180°+∠A=180°+50°=230°,故选:A.8.解:∵BD,CD分别是∠ABC与外角∠ACE的平分线,∴∠DCE=∠ACE,∠DBC=∠ABC,∵∠ACE﹣∠ABC=∠A=70°,∴∠D=∠DCE﹣∠DBC=∠A=35°,故选:B.9.解:∵∠A=150°,∴∠ABC+∠ACB=180°﹣∠A=30°.∵∠A1BA=∠ABC,∠A1CA=∠ACB,∴∠A1BC+∠A1CB=2(∠ABC+∠ACB)=60°,∴∠A1=180°﹣(∠A1BC+∠A1CB)=120°.同理可得:∠A2=90°,∠A3=60°,…,∠A n=180°﹣30°•(n+1),∴当∠A n>0°时,180°﹣30°•(n+1)>0°,解得n<5,∴至多能进行4步.故选:B.10.解:∵截去一个角后边数可以增加1,不变,减少1,∴原多边形的边数是7或8或9.故选:C.二.填空题(共8小题,满分24分,每小题3分)11.解:加上EF后,原不稳定的四边形中具有了稳定的三角形,故这种做法根据的是三角形的稳定性.12.解:①∵∠A+∠B=∠C,∠A+∠B+∠C=180°,∴2∠C=180°,∠C=90°,则该三角形是直角三角形;②∠A:∠B:∠C=1:2:3,∠A+∠B+∠C=180°,∴∠C=90°,则该三角形是直角三角形;③∠A=90°﹣∠B,则∠A+∠B=90°,∠C=90°.则该三角形是直角三角形;④∠A=∠B=∠C,则该三角形是等边三角形.故能确定△ABC是直角三角形的条件有①②③.13.解:设所求多边形的边数是x,则(n﹣2)•180°=1620,解得n=11.14.解:∵∠B=40°,∠ACD=120°,∴∠A=120°﹣40°=80°,∴∠A的余角是10°,故答案为:10°.15.解:由题意得,解得:<x<8,故答案为:<x<8.16.解:∵∠A=100°,∴∠ABC+∠ACB=80°,∵∠1=∠2,∠3=∠4∴∠2+∠4=∠ABC+∠ACB=40°,∴∠BOC=180°﹣∠2﹣∠4=140°故答案为:140°17.解:在△ABC中,∠A=10°,∠ABC=90°,在△AED中,∠FDE是它的一个外角,∴∠FDE=∠A+∠AED,∵∠ADE=∠EDF、∴∠ADE=∠EDF=90°∴∠CED=90°﹣∠A=80°∵∠CED=∠FEG,∴∠FEG=80°.在△AEF中,∠FEG是它的一个外角,∴∠FEG=∠A+∠F,∴∠F=∠FEG﹣∠A=80°﹣10°=70°.故答案为:70°.18.解:连接AD,在△AOD和△BOC中,∵∠AOD=∠BOC,∴∠B+∠C=∠1+∠2,∴∠B+∠C+∠BAF+∠EDF=∠1+∠2+∠BAF+∠EDF=∠EDA+∠F AD,∵∠EDA+∠F AD+∠E+∠F=360°,∴∠BAF+∠EDF+∠B+∠C+∠E+∠F=360°,故答案为:360°.三.解答题(共9小题,满分66分)19.解:图1,x°=360°﹣70°﹣90°﹣150°=50°,则x=50;图2,x°=180°﹣(360°﹣73°﹣90°﹣82°)=65°,则x=65;图3,x°+(x+30)°+60°+x°+(x﹣10)°=(5﹣2)×180°,解得x=115.20.解:已知:△ABC,求证:∠BAC+∠B+∠C=180°,证明:过点A作EF∥BC,∵EF∥BC,∴∠1=∠B,∠2=∠C,∵∠1+∠2+∠BAC=180°,∴∠BAC+∠B+∠C=180°.即知三角形内角和等于180°.21.解:∵∠ACD是△ABC的外角,∴∠ACD=∠B+∠BAC=30°+80°=110°,∵CE是∠ACD的平分线,∴∠ECD=∠ACD=×110°=55°,∵∠ECD是△EBC的外角,∴∠ECD=∠B+∠E,∴∠E=∠ECD﹣∠B=55°﹣30°=25°.答:∠E的度数是25°.22.解∵AD⊥BC,∴∠ADC=90°,∵∠C=80°,∴∠CAD=180°﹣90°﹣80°=10°,∵∠BAC=60°,AE是∠BAC的角平分线,∴∠EAC=∠BAE=30°,∴∠EAD=∠EAC﹣∠CAD=30°﹣10°=20°,∠ABC=180°﹣∠BAC﹣∠C=40°,∵BF是∠ABC的角平分线,∴∠ABO=20°,∴∠BOA=180°﹣∠BAO﹣∠ABO=180°﹣30°﹣20°=130°.故∠DAE,∠BOA的度数分别是20°,130°.23.(1)∵∠B=42°,∠C=78°,∴∠BAC=180°﹣∠B﹣∠C=60°,∵AD平分∠BAC,∴∠BAD=∠BAC=30°,∴∠ADC=∠B+∠BAD=42°+30°=72°;(2)如图所示,过A作AE⊥BC于E,∴∠AEB=90°,∴∠DAE=180°﹣∠AED﹣∠ADE=180°﹣90°﹣72°=18°.24.解:(1)∵a,b,c分别为△ABC的三边,a+b=3c﹣2,a﹣b=2c﹣6,∴,解得:2<c<6;(2)∵△ABC的周长为18,a+b=3c﹣2,∴a+b+c=4c﹣2=18,解得c=5.25.解:(1)∵BP和CP分别是∠B与∠C的平分线,∴∠1=∠2,∠3=∠4.∴∠2+∠4=(180°﹣∠A)=90°﹣∠A,∴∠BPC=90°+∠A.∴当∠A=70°时,∠BPC=90°+35°=125°.(2)同(1)可得,当∠A=112°时,∠BPC=90°+56°=146°.(3)同(1)可得,当∠A=α时,∠BPC=90°+.α26.解:(1)①∵∠B=30°,∠C=70°,∴∠BAC=180°﹣(30°+70°)=80°,∵AD平分∠ABC,∴∠CAD=∠BAC=40°,∵AE⊥BC,∴∠AEC=90°,∴∠CAE=90°﹣70°=20°,∴∠DAE=∠CAD﹣∠CAD=20°.故答案为80,20.②∵∠ADC=180°﹣∠CAD﹣∠C=180°﹣40°﹣70°=70°,∴∠FDE=∠ADC=70°,∵FE⊥BC,∴∠FED=90°,∴∠DFE=90°﹣∠FDE=20°.(3)∵AD平分∠ABC,∴∠BAD=∠CAD,∵AE平分∠BEC,∴∠AEB=∠AEC,∵∠C+∠CAE+∠AEC=180°,∠B+∠BAE+∠AEB=180°,∴∠C+∠CAE=∠B+∠BAE,∵∠CAE=∠CAD﹣∠DAE,∠BAE=∠BAD+∠DAE,∴∠C+∠CAD﹣∠DAE=∠B+∠BAD+∠DAE,∴2∠DAE=∠C﹣∠B=40°,∴∠DAE=20°.27.解:(1)∵BD平分∠ABC,BE平分∠CBF,∴∠DBC=ABC,∠CBE=CBF,∴∠DBC+∠CBE=(∠ABC+∠CBF)=90°,∴∠DBE=90°;(2)∵CD平分∠ACG,BD平分∠ABC,∴∠DCG=ACG,∠DBC=ABC,∵∠ACD=∠A+∠ABC,∴2∠DCG=∠ACF=∠A+∠ABC=∠A+2∠DBC,∵∠DCG=∠D+∠DBC,∴2∠DCG=2∠D+2∠DBC,∴∠A+2∠DBC=2∠D+2∠DBC,∴∠D=A=35°;(3)由(2)知∠D=A,∵∠A=α,∴∠D=,∵∠DBE=90°,∴∠E=90°﹣α.故答案为:,90°﹣.。
人教版八年级英语上册Unit 8 检测题
八年级英语Unit 8单元检测竹笮中学温泳海同学们,请动动你们聪明的头脑,挥挥你们灵活的小手,你会答出一份令自己满意的答卷的。
加油吧!!I. 词汇。
(10分)A)根据句意和首字母提示补全单词。
(5分)1. L______,I passed the important test yesterday .2.It's raining hard outside .Put on your r_______.3.In England ,if you go out in the morning ,you'd better take an u_____ with you .4. If you work hard ,you'll have a great f_____5. He cane first in the Beauty C___________.B) 根据句意,用括号内所给词的适当形式填空。
(5分)6. On my way home I met a famous ________(act) yesterday.7. I must ________ (winner) a prize this term.8. ________(unfortunate) I don't have enough money to travel abroad.9. I know many ________ (visit) come to China every year.10. They always have fun ________(talk) to each other.II. 单项选择。
(10分)11. He has ________ to tell us.A. something elseB. anything elseC. else somethingD. else anything12. -Were there any seals in the zoo?-________.A. Yes, there weren'tB. No, there weren'tC. Yes, there wasD. No, there were13. Jack likes Chinese, ________ he doesn't like maths.A. butB. orC. soD. and14. He was not at home ________.A. last nightB. tomorrowC. nowD. today15. Would you please________ this box to the next room?A. takeB. bringC. putD. get16. -Let's play computer games.- ________.A. It doesn't matterB. No, I don'tC. That sounds really boringD. It's nothing17. The manager gave the staff (职员) a day ________.A. awayB. offC. farD. of18. It rained ________ last Sunday. They had to stay at home.A. all the dayB. all daysC. the all dayD. all day19. I ________ pizza for lunch. It was terrible.A. hadB. watchedC. boughtD. saw20. -What do you want to be ________?-An English teacher.A. in the futureB. on the futureC. in futureD. at the futureIII. 汉译英。
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八年级英语寒假作业(十七)---- Units 8~9单元检测一、单项选择(每小题1分,共10分)( ) 1. --- ___ was your school trip ? --- It was interesting .A.HowB. WhatC. How aboutD. What about( ) 2. The science teacher was very happy __the students cleaned the bus after the trip.A. soB. butC. orD. because( ) 3. Did you have fun _____ ?A. to campB. to campingC. campingD. camped( ) 4. The students in class work hard _____ .A. all a dayB. all dayC. all daysD. all the day( ) 5. Sally often helps her mother _____ some housework .A. doesB. to doesC. doD. doing( ) 6. --- _____ was he born ? --- He was born in 1992 .A. WhereB. WhatC. WhyD. When( ) 7. How long did he _____ TV last night ?A. watchB. watchedC. watchesD. watching( ) 8. The grandfather _____ all his free time with his grandson .A. takesB. spendsC. bringsD. pays( ) 9. Laura _____ a skating champion at the age of ten .A. turnedB. becomesC. becameD. becomed( ) 10. In October 2000, he took part in _____ Chopin International Piano Competition In Poland .A.the 14thB. 14C. the 14D. 14th二、完形填空(每小题1分,共10分)John is a famous writer now. But he said he was not a 11 student when he was young. He was often late for 12 and didn't like doing his homework. Sometimes, he slept in class while(当……时候)the teacher was teaching. He didn't understand much, 13 he always thought he understood everything. One day,the teaeher 14 the students a question,“When Jack was ten years old, his brother Bob 15 twenty. Jack is fifteen now and 16 is his brother Bob?”John said,“That's easy. Bob is twice as old as Jack, so he is now thirty.”Another time, the 17 in a science class asked,“When it thunders(打雷),18 do we always see the light before we 19 the sound ?”“But,Miss,”said John quickly,“don't you 20 our eyes are in front of our ears ?”( )11、A.good B.tall C.rich D.fat( )12、A.sleep B.lunch C.class D.play( )13、A.so B.and C.or D.but( )14、A.sent B.asked C.told D.found( )15、A.is B.was C.are D.were( )16、A.how many B.how old C.what D.who( )17、A.teacher B.farmer C.worker D.policeman( )18、A.what B.when C.where D.why( )19、A.break B.make C.hear D.smell( )20、A.read B.hope C.study D.know三、阅读理解(一)(每小题2分,共20分)(A)Yesterday, my father went to work by train, but he left his umbrella in one of the compartments(火车车厢).He told a conductor about it and they began to look for the umbrella. “Which compartment did you leave your umbrella in?”the conductor asked. But my father couldn't remember it. The conductor found an umbrella in the first compartment,but it wasn't my father's. It was a woman's umbrella. Then they went to the next compartment and found another umbrella, but this wasn't my father's ,either.At last they came to the third compartment. They found it there! The conductorsaid“We found three. People are so forgetful!”根据短文内容,选择正确答案。
( )21、How did my father go to work ?A.By trainB.On footC.By bikeD.By bus( )22、My father left his in one of the compartments.A.bagB.coatC.umbrellaD.raincoat( )23、found an umbrella in the first compartment, but it wasn't my father's.A.My fatherB.One my father's friendsC.My motherD.The conductor ( )24、They found umbrella in the next compartment.A.my father'sB.anotherC.otherD.the other( )25、At last they found unbrellas in the three compartments.A.twoB.fourC.threeD.five( B )We are learning English, but how can we learn English well? A student can know a lot about English, but maybe he can’t speak English.If you want to know how to swim, you must get into the river. And if you want to be a football player, you must play football.So, you see. You can learn English only by using it. You must speak English to your classmates and also you must write something sometimes. Then one day, you may find your English very good.( )26. You know a lot about English but maybe ________.A. you can’t use itB. you can study itC. you can’t study itD. you can speak ( )27. You must get into the river ________.A. to catch a fishB. to go boatingC. to learn how to swimD. to play with water ( )28. Do you want to be a football player? Please ________.A. buy a good footballB. play footballC. watch others play footballD. put your football away ( )29. From the passage we know “________”.A.You know an apple good or not if you eat it.B.You can do anything if you don’t know how to do itC.You must speak English before you know how to use itD.Swimming is a good example for you to know English ( )30. If you want to study English well, you must often ________.A. speak EnglishB. write in EnglishC. listen to EnglishD. do all of A, B and C八年级英语寒假作业(十八)---- Units 8~9单元检测四、词形变换。