In the parallelogram ABCD, make a straight line AF through a, cross BC and E, and cross DC extension line to F. it shows that the area of triangle ABF and ade is equal

In the parallelogram ABCD, make a straight line AF through a, cross BC and E, and cross DC extension line to F. it shows that the area of triangle ABF and ade is equal

It is proved that the ∵ quadrilateral ABCD is a parallelogram
S △ ABF = 1 / 2S quadrilateral ABCD
S △ ade = 1 / 2S quadrilateral ABCD
∴S△ABF=S△ADE