Question

看图，长方形ABCD的面积是16平方厘米，E、F都是所在边的中点，求三角形AEF的面积。

Answer 1

阴S=16-16/4-16/4-16/8
=16-4-4-2
=6 (平方厘米)

Answer 2

设AD=BC=a
AB=CD=b
BE=CE=a/2
CF=DF=b/2
ab=16
SΔAEF=ab-SΔABE-SΔECF-SΔADF
=ab-1/2BE*AB-1/2CE*CF-1/2AD*DF
=ab-1/2*a/2*b-1/2*a/2*b/2-1/2*a*b/2
=ab-ab/4-ab/8-ab/4
=3ab/8
=3*16/8
=6 cm^2