The rubber ball, in this case, can be considered a circle with a circumference of 13 inches. So, we can find the diameter of the rubber ball using the formula [tex]C=\pi d[/tex] or [tex]d=\frac{C}{\pi }[/tex]. That is
[tex]d=\frac{C}{\pi }=\frac{13\:inches}{\pi }=\frac{13}{\pi }=4.14\:inches[/tex]
Therefore, the diameter is greater than 4 inches and less than 5 inches. That means the smallest box that the ball will fit into with the top on is the 5 inches box.