Answer:
Area of shaded part ABCEF = 66 sq.cm
Explanation:
AB = 8cm
CD = 8cm
Let DE = x cm
CE = 3x cm
CD = CE + DE = 8cm
x + 3x = 8
4x = 8
x = 8/4 = 2 cm
DE = 2cm
CE = 3 * 2 = 6 cm
Area of triangle ADE = 1/2 * base * height
= 1/2 * DE * AD
= 1/2 * 2 * 11 = 11 sq. cm
Area of triangle AEF = Area of triangle ADE = 11 sq. cm
Area of Rectangle ABCD = l * b = 8 * 11 = 88 sq.cm
Area of shaded part ABCEF = Area of Rectangle ABCD - (Area of triangle AEF + Area of triangle ADE)
= 88 - ( 11 + 11 ) = 88 -22 = 66 sq.cm