REF.Image
Given : BC||DE
To prove : area ΔABE = area ΔACD
A(ΔBCE)=A(ΔBCD) - (i).... (triangle with same base BC and between some parallel lines BC and DE)
Now,
A(ABE)=A(ΔACB)+A(BCE)−(ii)
A(ΔABE)=A(ΔACB)+A(ΔBCD)... [from (i)]
A(ΔABE)=A(ΔACD)
Since A(ACB)+A(ΔBCD)=A(ΔACD)