更新1:
@戇戇居士 Thank you.
ABCD is a quadrilateral. AB is parallel with DC, and angle A + angle B = 180°. Prove that ABCD is a parallelogram?
回答 (1)
2016-07-03 12:19 pm
✔ 最佳答案
∠DAB + ∠ABC = 180° (given)Hence, DA // BC (int. ∠s. supplementary)
AB // DC (given)
ABCD is a parallelogram (two pairs of opp. sides //)
收錄日期: 2021-04-18 15:12:59
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160703041145AAlgb7w