Find EF
2011-01-14 7:24 am
圖片參考：http://imgcld.yimg.com/8/n/HA00837720/o/701101130151913873369050.jpg
AED,BEC and BFD are straight lines,AB//CD//EF,find EF=?
回答 (1)
2011-01-14 7:38 am
✔ 最佳答案
△DEF~△DAB (A.A.) => EF/AB=DF/DB...(*)△BEF~△BCD (A.A.) => EF/CD=BF/DB...(**)
(*)+(**):
(EF/AB)+(EF/CD)=(DF/DB)+(BF/DB)
EF[(1/AB)+(1/CD)]=(DF+BF)/DB
EF[(1/24)+(1/16)]=DB/DB
EF[(1/24)+(1/16)]=1
EF=1/[(1/24)+(1/16)]
EF=48/5
收錄日期: 2021-04-22 00:55:38
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110113000051KK01519