Posted by Please Help on Tuesday, March 1, 2011 at 10:46pm.
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.

Math  MathMate, Tuesday, March 1, 2011 at 11:37pm
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. 
Math  Anonymous, Thursday, May 9, 2013 at 12:39pm
approximately 12.27 in^3