Question

if a cylindrical can hold three balls with no room to spare, explain how to find the volume of the air that surrounds the balls in the can. Let the balls have a diameter of six inches. draw diagrams to help you solve this.

Answer 1

If there was only one ball in the can,
you would take the volume of the can,
and subtract from it the volume of the ball.

That would give you the amount of space that this air or empty regions are taking up.