Fun Equation. I made a Dataset Table which has some sports listed and the radius (average radius in some cases) of the balls used to play that sport. This equation will allow you to select a Sport (or ball) and it will return the data from the Table representing the ball size in millimeters.
There is a Dataset which has two columns; Sport and Diameter.
This equation will access the dataset and retrieve the ball diameter, in millimeters, for the selected Sport.
The dataset currently includes the following Sports: