1. Area of the right angled ∆ = 1/2 × base × height
height = 16m
base = √20² – 16²
= √400 –256
= √144
= 12 m
Area of the unshaded portion
= 1/2 × base × height
= 1/2 × 12 × 16
= 96m²
2. Area of the rectangle = 300ft × 150ft
= 45000sq. ft
Area of the shaded portion = 100² + (1/2×b×h)
= 10000 + (1/2×120×150)
= 10000 + 9000
= 19000 sq. ft
Area of the unshaded part of the rectangle
= (45000 – 19000)sq. ft
= 26000 sq. ft