Answer:
546 ft³
Step-by-step explanation:
In the figure attached, the top view of the pool is shown. It can be decomposed into a trapezoid which height is 12 ft and which bases are 9 ft and 11 ft; and a rectangle which height is 1.5 ft and and it base is 11 ft.
Area of the trapezoid: (9 + 11)/2 * 12 = 120 ft²
Area of the rectangle: 1.5*11 = 16.5 ft²
Total area: 120 + 16.5 = 136.5 ft²
Volume of the pool: Total area * deep = 136.5 * 4 = 546 ft³
