呢題要用希羅公式*
在△ABC中，設 s = 1/2 (a + b + c)而 s- a = 5.7cm, s - b = 9.3cm 及 s - c = 7.4cm。求△ABC的周界。
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三角形面積
2009-03-29 8:28 am
回答 (1)
2009-03-29 8:45 am
✔ 最佳答案
s = (a + b + c)/2 ....(i)s-a = 5.7
s-b = 9.3
s-c = 7.4
(s-a)+(s-b)+(s-c) = 5.7+9.3+7.4
3s-(a+b+c) = 22.4 .....(ii)
Sub (i) into (ii),
3(a+b+c)/2 -(a+b+c) = 22.4
(3/2-1)(a+b+c) = 22.4
a+b+c = 44.8
所以,△ABC的周界為44.8 cm
參考: myself
收錄日期: 2021-04-24 09:58:28
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090329000051KK00058