The ball can be modeled as a sphere. The volume of a sphere is given by: V = (4/3) * pi * r ^ 3 Where, r: radius of the sphere. We have then: V = (4/3) * pi * (18/2) ^ 3 V = 3053.6 in ^ 3 Answer: the volume of a beach ball with a diameter of 18 inches is: V = 3053.6 in ^ 3
