As follows:
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maths~~~~~~~~
2010-03-20 2:05 am
回答 (2)
2010-03-20 2:26 am
✔ 最佳答案
ㄥBDC = 180 - 30 - 35 - 60 = 55°BD / sin(35+60)° = 5 / sin55°
BD = 6.08065cm
ㄥBAC = 180 - 30 - 35 - 80 = 35°
△ABC等腰,AB = BC = 5cm
AD^2 = 5^2 + 6.08065^2 - 2 * 5 * 6.08065 cos80°
AD = 7.17cm
2010-03-20 5:55 am
△BDC : A+30°+35°+60°=180°(△內角和)
A=55°
BD / sin(35°+60°) = 5 °/ sin55°
BD = 6.08065(cm)
△BAC = B+80°+30°+35°=180°(△內角和)
B=65°
△ABC等腰,AB = BC = 5cm
AD^2 = 5^2 + 6.08065^2 - 2 * 5 * 6.08065 cos80°
AD = 7.17cm
2010-03-20 16:09:13 補充：
LKY
A=55°
BD / sin(35°+60°) = 5 °/ sin55°
BD = 6.08065(cm)
△BAC = B+80°+30°+35°=180°(△內角和)
B=65°
△ABC等腰,AB = BC = 5cm
AD^2 = 5^2 + 6.08065^2 - 2 * 5 * 6.08065 cos80°
AD = 7.17cm
2010-03-20 16:09:13 補充：
LKY
收錄日期: 2021-04-21 22:09:54
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100319000051KK00965