What is the area of the triangle ADE in the following figure ?

Answer:
Step-by-step explanation:
Hello
Area triangle DCE :
10 x (8/2) / 2 = 10 x 4 / 2 = 20 cm^2
Area triangle ABE = Area triangle DCE
Area ABCD :
10 x 8 = 80 cm^2
Area triangle AED :
Area ABCD - 2 area DCE
= 80 - 2 x 20
= 80 - 40
= 40 cm^2