As follows:
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maths~~~~~~
2010-03-03 9:46 pm
回答 (1)
2010-03-03 10:01 pm
✔ 最佳答案
BD^2=BC^2+CD^2-2BC*CD*cos(BCD)=>BD^2=4^2+6^2-2(4)(6)cos(120)
=>BD=8.7178 cm
AD=AB=10 cm givien
cosABD = (BA^2+BD^2-AD^2)/(2BA*BD) =>ABD= 64.15806724
cosDBC = (BD^2+BC^2-DC^2)/(2*BD*BC)=>DBC= 36.5877555
=>ABC = ABD+DBC = 100.7025823
=>AC^2=BC^2+AB^2-2*AB*BCcosABC
=>AC=11.44 cm//
收錄日期: 2021-04-23 20:43:25
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100303000051KK00499