如图,矩形纸片ABCD中,AB=3,BC=4,现将A、C重合后,使纸片压平,设折痕为EF,使确定重叠部分的面积等于________.
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解析分析:重叠部分为△AEF,底为AF,高为AB,根据折叠的性质可知∠AEF=∠CEF,AE=EC,由平行线的性质可知∠CEF=∠AFE,故有∠AEF=∠AFE,可知AE=AF=EC,设AE=AF=EC=x,则BE=4-x,在Rt△ABE中,运用勾股定理列方程求解.
解答:由折叠的性质可知∠AEF=∠CEF,AE=EC,由平行线的性质可知∠CEF=∠AFE,∴∠AEF=∠AFE,∴AE=AF=EC,设AE=AF=EC=x,则BE=4-x,在Rt△ABE中,由勾股定理得AB2+BE2=AE2,即32+(4-x)2=x2,解得x=,∴S△AEF=×AF×AB=××3=.故本题