How to find out how big a ball is? Ok, This is probably a really simple question but. I need to know how I can find out how big a ball is. For example, a tennis ball is 2 1/2 inches big, but how do you find that?
Though, for reference, the explanation and answer to this question needs to be as simple as it can possibly get. I have a learning disability that heavily affects my mathematics capabilities and severe Dyscalculia. This explanation here probably makes me sound pretentious, but a lot of people don't understand or they throw too many numbers at me and get frustrated when I haven't said anything before hand. I'm sorry if it does, but I'm covering all my bases lol. 
Any help on how to figure this question out is very much appreciated!

Make a cylinder of paper that is large enough to enclose the ball.  Put the ball on a table and close the cylinder around the ball.  Mark where the paper's (verticle) edge meets the other side of the ball while the cylinder is perpendicular to the table. This allows you to measure the circumference.  Then the division by $\pi$ ($3.1418$) gives the diameter, which is the width of the ball.  The old approximation for $\pi$ is $\frac{22}7$, so you can mulitply by $7$ and divide by $22$ to get the number you are looking for.
