求平行四邊形的解！！！
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急~求平行四邊形的解！
2011-11-06 8:44 pm
回答 (2)
2011-11-06 9:21 pm
✔ 最佳答案
∠DEC=x(alt. ∠s , AD//BC)∵CE=CD
∴∠DEC=∠CDE=x(alt. ∠s , AD//BC)
∠C=180°-70°(int. ∠s, AB//DC)
=110°
110°+2x=180 (∠ sum of △)
x=35°
2011-11-07 12:30 am
∠DEC=x (alt∠, AD//BC)
By CE=CD (given)
∠DEC=∠CDE=x
∠ABC=∠ADC (平行四邊形對角相等)
70°=2x
x=35°
By CE=CD (given)
∠DEC=∠CDE=x
∠ABC=∠ADC (平行四邊形對角相等)
70°=2x
x=35°
參考: me
收錄日期: 2021-04-13 18:20:16
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20111106000051KK00378