幾何一問

[ruby0519]

如附件
謝謝老師

[thepiano]

連 AG
令 △BEG = x，△AFG = y
△AEG = 2x
ABCD = 4△ABF = 12x + 4y
△BCE = (1/6)ABCD = 2x + (2/3)y
△BCF = (1/2)ABCD = 6x + 2y
△BCG = x + (2/3)y
△CFG = 5x + (4/3)y

△ABG：△AFG = BG：FG = △BCG：△CFG
3x：y = [x + (2/3)y]：[5x + (4/3)y]
x = (2/15)y

所求 = (3x + y)：3x = 7：2