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过B做BE⊥AD,过C做CF⊥BE∠A = 60°AB = 4∴AE = 2,BE= 2√3∵BE⊥AD,∠D = 90°∴四边形BCDE是直角梯形.∵∠ABC = 90°,∠A = 60°∴∠ABE = 30°,∠EBC = 60°∴CF = √3(BF) = √3(BE-CD) = √3(2√3-2)=6-2√3 = ED∴四边形ABCD的面积=Rt△ABE + 直角梯形BCDE= 2*2√3/2 + (2√3 + 2)*(6-2√3)/2= 6√3打个小广告:qq初中解题群:96757169
1年前
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