Maths
2015-03-18 3:46 pm
ABC is a triangle with AB = 3, BC = 4 and angle ABC = 68 degree. P is a point on AC such that BP is the angle bisector of angle ABC, find length of the angle bisector BP. ( correct to 3 sig. fig.)
回答 (1)
2015-03-18 4:53 pm
✔ 最佳答案
圖片參考：https://s.yimg.com/rk/HA00108663/o/756613404.jpg
In triangle ABC,
AC2 = 32 + 42 - 2(3)(4) cos 68 => AC = 4.00
cos∠BAC = (32 + 4.002 - 42) / [2(3)(4.00)] => ∠BAC = 68.0
In triangle ABP,
∠APB = 180 - 34 - 68.0 = 78.0
BP / sin 68.0 = 3 / sin 78.0 => BP = 2.84
2015-03-18 08:54:08 補充：
個 2 次方跌左落地下 >.
參考: knowledge
收錄日期: 2021-04-28 14:41:14
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20150318000051KK00010