this course will help you gain the ideas, owledge and skills you need to write fundraising copy that produces more impressive and profitable results.5.1 1. 对顶角
一、选择题
1.学习了对顶角后,教师画了如图K-46-1所示的四个图形,那么∠1和∠2是对顶角的图形有( )
图K-46-1
A.1个 B.2个 C.3个 D.4个
2.如图K-46-2,直线AB与CD相交于点O,EO⊥AB,则∠1与∠2( )
图K-46-2
A.是对顶角 B.相等 C.互余 D.互补 3.如图K-46-3,直线AB,CD相交于点O,且∠AOD+∠BOC=236°,则∠AOC的度数为( )
图K-46-3 A.62° B.72° C.124° D.144°
4.如图K-46-4,直线AB和CD相交于点O,射线OM平分∠AOC.若∠AOM=38°,则∠BOD等于( )
图K-46-4
A.38° B.52° C.76° D.142°
5.如图K-46-5,三条直线l1,l2,l3相交于点O,则∠1+∠2+∠3等于( )
图K-46-5
A.90° B.120° C.180° D.360°
1
this course will help you gain the ideas, owledge and skills you need to write fundraising copy that produces more impressive and profitable results.二、填空题
6.如图K-46-6,直线AB和CD相交于点O,则∠3的对顶角是________,∠2的邻补角是________.若∠2=120°,则∠1=________°,∠4=________°.
图K-46-6
7.如图K-46-7,点B,O,D在同一条直线上,若OA的方向是北偏东70°,则OD的方向是________.
图K-46-7 8.如图K-46-8,直线AB与直线CD相交于点O,∠BOE=90°,垂足为O.若∠AOC=65°,则∠DOE的度数是________.
图K-46-8
9.如图K-46-9,直线AB,CD相交于点O,∠COF=90°,OF平分∠AOE.若∠BOD=25°,则∠EOF的度数为________.
图K-46-9
三、解答题
10.下列两个图形中各有几对对顶角?请分别写出来.
图K-46-10
2
this course will help you gain the ideas, owledge and skills you need to write fundraising copy that produces more impressive and profitable results.11.如图K-46-11,直线AB,CD相交于点O,∠DOB∶∠BOC=2∶1,求∠AOC的度数.
图K-46-11
12.如图K-46-12所示,直线AB交CD于点O,OE平分∠BOD,OF平分∠BOC,∠AOD∶∠DOE=4∶1,求∠AOF的度数.
图K-46-12
13.如图K-46-13所示是小兵自制的对顶角“小仪器”示意图.
(1)将三角尺ABC的AC边延长且使AC固定;(2)将另一三角尺CDE的直角顶点与前一个三角尺的直角顶点重合;(3)延长DC,∠PCD与∠ACF就是一对对顶角.
已知∠1=30°,则∠ACF的度数是多少?
图K-46-13
3