The materials to be used to make the rubber ball will cover the circumference of the ball. Hence, the cubic inches of material to be used represent the volume of the sphere with diameter = 3 inches (radius = 3 / 2 = 1.5 inches). The volume of a sphere is given by V = 4/3 pi r^3 = 4/3 pi x (1.5)^3 = 14.14 cubic inches.