A food manufacturer has a large vat shaped like a right circular cylinder with a diameter of 10 feet and a height of 20 feet. A diagram of the
vat and the repair ladder is shown below.To the nearest cubic foot, what is the volume of liquid that is in the vat when it is filled to a depth
of 18 feet? (Note: The volume of a cylinder is given by V-zr²h, where r is the radius and his the height.)