Using 3.14 for PI.
The radius of a ball and the can is half the diameter = 1.25
The height of the can is the height of 3 diameters = 7.5
Volume of one tennis ball:
4/3 x PI x 1.25^3 = 8.18 cubic inches.
Volume of 3 tennis balls: 3 x 8.18 = 24.54 cubic inches.
Volume of can:
PI x 1.25^2 x 7.5 = 36.80 cubic inches.
Space = 36.80 - 24.54 = 12.26 cubic inches.
