2000 ce maths mc Q54

2009-12-24 1:23 am
I would like to ask how to solve 2000 ce maths mc Q54.

回答 (2)

2009-12-24 8:52 am
✔ 最佳答案
point F is on AB, and point G is on CD , FG ⊥AB, FG ⊥ DC
area of △ABC = 1/2 (AB)(FG) = 4+5 =9, FG = 18/AB
area of △ABE = 1/2 (AB)(FE) =4, FE = 8/AB

∴ FG : FE = 18 :8 = 9:4
FE + EG : FE = 9:4
EG : FE = 5:4
∠ABE =∠CDE , ∠BAE =∠DCE (CORR. ∠s AB∥ DC)
∠AED = ∠CED (VERT. OPPO. ∠s)
∴ △ABE~△CDE (AAA)

∴area of △CDE/area of △ABE = [(EG)/(FE)]^2 = [5/4}^2 = 25/16
area of △CDE = 4(25)/16 = 6.25 CM^2
2009-12-24 8:51 pm
thank you very much!


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