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更新1:
高二數學考題
已知三角形ABC垂心H,.....,求ABC面積
2014-11-01 8:06 pm
已知三角形ABC垂心H,BH=5,CH=1,cos(∠ACB)=1/(5√2),求ABC面積
圖形請參閱
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https://www.facebook.com/groups/637774222948895/798240203568962/
回答 (2)
2014-11-02 5:05 pm
✔ 最佳答案
∠ECD + ∠EHD = 180° = ∠EHD + ∠BHD ∠BHD = ∠ECD = ∠ACB DH = BH cos(∠BHD) = 1/√2 CH = 1, ∠DCH = ∠BCF = ∠CBF = ∠CBA =45° CD = DH = 1/√2BD = BH sin(∠BHD) = 5 x 7/(5√2) = 7/√2 BC = BD + CD = 8/√2 = 4√2 AD = BD = 7/√2 △ABC = (7/√2)( 4√2)/2 = 14圖片參考：https://s.yimg.com/rk/AD09210203/o/898921182.jpg
2014-11-02 4:36 am
BH=5,CH=1
圖的比例未免也差太多了，還是....??
圖的比例未免也差太多了，還是....??
收錄日期: 2021-04-21 00:38:26
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20141101000015KK01138