First we need to find the volume of the three tennis balls:
V = 4/3 x Pi x r^3
V = 4/3 x Pi x 1.25^3
V = 8.18
Since there are three tennis balls:
8.18 x 3 = 24.54
Then we need to solve for the cylinder:
V = Pi x r^2 x h
V = Pi x 1.25^2 x (2.5 x 3)
V = 36.81
Then we need to find the total amount of space between the tennis balls and the cylinder
38.81 - 24.54 = 12.27 inches
12.27 inches to the nearest tenth is 12.30 inches