maths~!
2008-06-15 11:20 pm
回答 (1)
2008-06-16 12:11 am
✔ 最佳答案
∵AO=CO (radius) (半徑)∴∠OAC=∠OCA
∠OCA=33°
∠OCA+∠OAC+∠AOC=180° (∠ sum of tri.) (三角形內角和)
∠AOC=114°
Let x be ∠COB.
arc AB: arc BC=2x:x (arcs prop. to ∠s at ⊙^ce) (圓周角與所對的孤成比例)
∴2x+x=114°
x=38°
∵∠BOA=2x
=2(38°)
=76°
參考: myself
收錄日期: 2021-04-23 20:32:33
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080615000051KK01429