如图,当∠______=∠______时,AB∥DC,依据是______;当∠1+∠2+∠D=180゜时,那么______∥______,依据是______.
题型:不详难度:来源:
如图,当∠______=∠______时,AB∥DC,依据是______;当∠1+∠2+∠D=180゜时,那么______∥______,依据是______.![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023082542-96870.png) |
答案
∵∠1=∠4, ∴AB∥DC(内错角相等,两直线平行), ∵∠1+∠2+∠D=180゜, ∴DA∥CB(同旁内角互补,两直线平行). |
举一反三
如图,填空并在括号内注明理由. (1)若∠A=∠3,则______∥______; (2)若∠2=∠E,则______∥______; (3)若∠A+∠ABE=180゜,则______∥______.![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023082537-91058.png) |
如图,直线c与直线a、b相交,∠1=47゜,当∠2=______时,a∥b.![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023082531-87660.png) |
如图,∠1=68゜,∠2=68゜,∠3=112゜,图中互相平行的直线有______.![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023082520-41615.png) |
如图所示,已知CD⊥DA,DA⊥AB,∠1=∠2. (1)AB与CD平行吗?为什么? (2)DF与AE平行吗?为什么?![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023082515-94794.png) |
如图,当∠A=∠CBE时,可以判定( )A.AB∥DC | B.AD∥BC | C.AD∥AE | D.BC∥DC |
![魔方格](http://img.shitiku.com.cn/uploads/allimg/20191023/20191023082512-35086.png) |
最新试题
热门考点