浙江省温州市乐清市育英学校普通班2018-2019学年八年级(上)月考数学试卷(9月份)

适用年级:初二
试卷号:641634

试卷类型:月考
试卷考试时间:2019/10/7

1.单选题(共7题)

1.
工人师傅常用角尺平分一个任意角.做法如下:如图所示,∠AOB是一个任意角,在边OAOB上分别取OM=ON,移动角尺,使角尺两边相同的刻度分别与MN重合.过角尺顶点C的射线OC即是∠AOB的平分线.这种做法的道理是(   )
A.HLB.SSSC.SASD.ASA
2.
如图,在△ABC中,AB=AC,且D为BC上一点,CD=AD,AB=BD,则∠B的度数为()
A.30°B.36°C.40°D.45°
3.
如图,将三角尺的直角顶点放在直线a上,a∥b,∠1=50°,∠2=60°,则∠3的度数为【   】
A.50°B.60°C.70°D.80°
4.
在直线l上依次摆放着七个正方形,已知斜放置的三个正方形的面积分别是1,2,3,正放置的四个正方形的面积依次是S1,S2,S3,S4,则S1+S2+S3+S4=(  )
A.4B.5C.6D.7
5.
如图,在生活中,我们经常会看见如图所示的情况,在电线杆上拉两条钢筋,来加固电线杆,这是利用了三角形的(  )
A.稳定性B.灵活性C.对称性D.全等性
6.
图中,三角形的个数为(  )
A.5B.6C.7D.8
7.
下列长度的三条线段能组成三角形的是(  )
A.1,2,3.5B.4,5,9C.20,15,8D.5,15,8

2.选择题(共3题)

8.

阅读下文并回答问题。

    There are 24 solar terms (节气) in China, and the Grain Rain(谷雨) is one of them. It falls on April 19 this year.

    This solar term is called the Grain Rain because it is known for “rain” that helps the grain grow. From its name, we can guess it means a time of more rain. So if you go out in the next two weeks, you may need to bring an umbrella with you.

    But this is a great time for planting crops. If you miss the time for planting during the Grain Rain, you will feel sorry later. So maybe you can try to plant some flowers or vegetables in your garden. When the spring rain falls, farmers begin to grow crops (庄稼). Farmers often say, “Spring rain is as precious (珍贵的) as oil.” It brings farmers hope for a good year ahead.

    There are also many interesting customs during the Grain Rain. In the northern part of China, people like to eat Chinese toon (椿芽) mixed with eggs. The food made during the Grain Rain tastes wonderful and is good for your stomach. In the southern part of China, the tea leaves are picked during the time. They are called Grain Rain tea, which is famous for its freshness and sweet smell.

9.经检测,刚挤出的牛奶中有两种分子式分别为C12H22O11和C1864H3012N168O221化学物质,它们分别是(  )
10.经检测,刚挤出的牛奶中有两种分子式分别为C12H22O11和C1864H3012N168O221化学物质,它们分别是(  )

3.填空题(共7题)

11.
如图,点ADBE在同一条直线上,ADBE,∠A=∠E,若要△ACB≌△EFD,则可添加一个条件_____.
12.
如图所示,要测量河两岸相对的两点AB的距离,在AB的垂线段BF上取两点CD,使BCCD,过DBF的垂线DE,与AC的延长线交于点E,若测得DE的长为20米,则河宽AB长为_____米.
13.
如图,在△ABC中,DBC上一点,ACCD,∠DAB=10°,∠B=5∠DAB,则∠C=_____.
14.
如图,在正方形ABCD中,边AD绕点A顺时针旋转角度),得到线段AP,连接PB,P
A.当△BPC是等腰三角形时,的值为______.
15.
如图,在Rt△ABC中,∠BAC=90°,AB=5,AC=12,AD是斜边BC上的中线,则AD=_____.
16.
如图,已知ABCD,∠A=20°,∠C=30°,则∠AEC=_____.
17.
在Rt△ABC中,一个锐角为25°,则另一个锐角为_____度.

4.解答题(共4题)

18.
如图,已知ACBD,∠CAB=∠DBA,求证:BCAD
证明:在△ABC和△BAD

∴△ABC≌△BAD (    
BCAD (    
19.
为了测出池塘两端AB的距离,小明在地面上选择了点EDC,使ACCDBCCE,且点ACD和点BCE分别都在一条直线上,只要量出DE的距离,就能知道AB的距离,你认为正确吗?
解:我认为    .(填空“正确”或“不正确”)
如果认为正确,请写出证明过程;认为不正确,请举出例子.
20.
如图,AD∥BC,∠A=90°,E是AB上的一点,且AD=BE,∠1=∠2.
(1)Rt△ADE与Rt△BEC全等吗?请写出必要的推理过程;
(2)△CED是不是直角三角形?请说明理由;
(3)若已知AD=6,AB=14,请求出请求出△CED的面积.
21.
如图,已知AC平分∠BADCEABECFADF,且BCCD
(1)求证:△BCE≌△DCF
(2)若AB=15,AD=7,BC=5,求CE的长.
试卷分析
  • 【1】题量占比

    单选题:(7道)

    选择题:(3道)

    填空题:(7道)

    解答题:(4道)

  • 【2】:难度分析

    1星难题:0

    2星难题:0

    3星难题:0

    4星难题:0

    5星难题:0

    6星难题:9

    7星难题:0

    8星难题:1

    9星难题:8