Safg/Sbcg = 1/4 :面积比等于相似比的平方
Safg/Sabg = 1/2 :分别以fg和bg为底,这两个三角形等高,面积比等于底边比
Safg/Sabcd = 1/12 :Safg=1/2 * af * h = 1/2 *(1/2 * ad)*(1/3 * ab)
= 1/12 * ad * ab
所以 Scgfd/Sabcd = 4/(12-1-2-4)= 4/5
Safg/Sbcg = 1/4 :面积比等于相似比的平方
Safg/Sabg = 1/2 :分别以fg和bg为底,这两个三角形等高,面积比等于底边比
Safg/Sabcd = 1/12 :Safg=1/2 * af * h = 1/2 *(1/2 * ad)*(1/3 * ab)
= 1/12 * ad * ab
所以 Scgfd/Sabcd = 4/(12-1-2-4)= 4/5