Answer:
11. 379.6 ft²
12. 450.5 in.²
Explanation:
11.
shaded area = area of square - area of semicircle
side = 25 ft
radius = 12.5 ft
shaded area = s² - 0.5πr²
shaded area = (25 ft)² - 0.5 × 3.14159 × (12.5 ft)²
shaded area = 379.6 ft²
12.
shaded area = area of circle - area of triangle
radius = 0.5 ×√(20² + 21²) in. = 14.5 in.
base = 20 in.
height = 21 in.
shaded area = πr² - bh/2
shaded area = 3.14159 × (14.5 in.)² - (20 in.)(21 in.)/2
shaded area = 450.5 in.²