圓 I 為三角形ABC的內切圓, D, E, F分別為切點, 若AB=19, BC=20, CA=17 則AF=? , BD=? , CE=? 謝謝?
回答 (1)
2016-02-18 1:26 pm
AF = AE , BF = BD , CD = CE
{
AF + BF = 19 , BD + CD = 20 , CE + AE = 17
⇒
AF + BD = 19 , BD + CE = 20 , CE + AF = 17
⇒
2(AF + BD + CE) = 19 + 20 + 17
AF + BC + CE = 28
⇒
AF = 28 - 20 = 8
BD = 28 - 17 = 11
CE = 28 - 19 = 9
{
AF + BF = 19 , BD + CD = 20 , CE + AE = 17
⇒
AF + BD = 19 , BD + CE = 20 , CE + AF = 17
⇒
2(AF + BD + CE) = 19 + 20 + 17
AF + BC + CE = 28
⇒
AF = 28 - 20 = 8
BD = 28 - 17 = 11
CE = 28 - 19 = 9
收錄日期: 2021-04-18 14:27:07
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160218050711AAHUb9W