f3 maths (triangle)?

2016-12-09 11:23 pm
AB┴ BC and DE is the perpendicular bisector of △ABC AB :8cm ,AC :10cm.

(a) prove AD=CD .
)b)find the perimeter of △BCD

回答 (1)

2016-12-10 5:24 am
Sol
(a)
在△ADE與△CDE中
AE=CE
∠AED=∠CED=90度
DE=DE
△ADE全等於△CDE (SAS)
AD=CD
(b)
BC^2=AC^2-AB^2=10^2-8^2=100-64=36
BC=6
△BCD周長=BC+BD+CD=6+(AB-AD)+CD=6+(8-CD)+CD=14


收錄日期: 2021-04-30 21:57:41
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20161209152304AA4Th8p

檢視 Wayback Machine 備份