f.3 四邊形(2)(急)!
2009-02-10 3:21 am
圖片參考：http://i41.photobucket.com/albums/e288/s0malia_0v0/af77d0de-1.jpg?t=1234178346
第二條都係諗唔到
又係截線+中線定理
回答 (2)
2009-02-10 7:53 am
✔ 最佳答案
因為CD:CB=1:1 & CE//BG所以CE:BG=1:2 (mid-point therom)
因為AB:BC=1:1 & BG//CF
所以BG:CF=1:2 (mid-point therom)
因為CE:BG=1:2 & BG:CF=1:2
所以CE:CF=1:4
CE:EF
=CE:(CF-CE)
=1:(4-1)
=1:3
2009-02-10 3:38 am
令CE=x﹐則由中點定理(考慮三角形BDG)BG=2x﹐再由中點定理(考慮三角形ACF)CF=4x﹐故EF=CF-CE=3x﹐CE:EF=1:3
收錄日期: 2021-04-26 13:05:48
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090209000051KK01433