In a parallelogram, opposite sides are equal. 5b = 4a These are not co-prime numbers. The value of b must be 4 and value of a must be 5. Area of Parallelogram = b × h = 120 5b × 3c = 120 bc =
120
15
= 8
Area of triangle ABX =
1
2
×3b×3c =
9bc
2
=
9×8
2
= 36 cm2 Now bc = 8 c =
8
b
=
8
4
= 2 cm. Area of triangle ZDY =
1
2
×a×c =
1
2
×5×2 =
10
2
= 5 Area of pentagon AXCYZ = 120 − (36 + 5) = 120 − 41 = 79 cm2