Answer:
135 ft²
Explanation:
see attached image
shaded area = total area (1) - unshaded triangular area (2)
1. area of a trapezoid = (a + b) * h/2
where a = 8, b = 18, h = 15
Area of trapezoid = (8 + 18) * 15/2 = 195 ft²
2. Area of unshaded triangle = 1/2 (8) 15 = 60 ft²
shaded area = 195 - 60 = 135 ft²