It’s a binomial cause there’s two terms
The volume of a cylinder is
(pi) (radius²) (height) .
Radius = 1/2 diameter.
Radius of this pool = (1/2) (18 ft) = 9 ft
The pool is a cylinder with height of 4.5 feet.
The water in it is also a cylinder, but only 4 ft high.
Volume of the water =
(pi) x (radius²) x (height)
= (pi) x (9 ft)² x (4 ft)
= (pi) x (81 ft²) x (4 ft)
= (pi) x (324 ft³) = 1,017.9 ft³ .