Question

如图,Rt三角形ABC中,角B=90读,AB=3,AC=5,将三角形ABC折叠

Answer 1

根据折叠,AE=CE

RT△ABC中,AB=3,AC=5,所以BC=4

AE+BE=CE+BE=BC=4

设BE长为X,则AE长为4-X

RT△ABE中

AB²+BE²=AE²

X²+3²=（4-X）²

X²+9=X²-8X+16

8X=7

X=7/8

S△ABE=1/2×BE×AB=1/2×7/8×3=21/16