Math
posted by Please Help .
Tennis balls withal diameter of 2.5 in. Are sold in cans of three. The can is a cylinder. What is the volume of the space in the can not occupied by tennis balls? Assume the balls touch the on the sides,top and bottom.

Height of cylinder, h
= 3 times the diameter of tennis balls
= 3*2.5"
= 7.5"
Diameter of cylinder, d
= diameter of tennis ball
= 2.5"
Volume of cylinder
= πd²h/4
Volume of each tennis ball, v
= 4π(d/2)³/3
Volume of three tennis balls
= 3v
= 4π(d/2)³
Interstitial space
= Volume of cylinder  volume of three balls. 
approximately 12.27 in^3