如图所示,正方形ABCD面积为20,AE=ED且EF=3FC,则三角形ABF的面积等于?
问题描述:
如图所示,正方形ABCD面积为20,AE=ED且EF=3FC,则三角形ABF的面积等于?
答
△ABF的面积=正方形ABCD面积-(△ECD+△AFE+△BCF﹚ =20-﹙1/2√20×√20×1/2+1/2√20×3/4√20×1/2-√20×1/4√20×1/2) &n...