Find the volume of 4ft by 2ft by 3ft rectangular prism with a cylinder hole, radius 6 in., through the center

Just subtract the volume of the cylinder from the volume of the rectangular prism.

Volume of rectangular prism = l x w x h = 4 x 2 x 3 = 24 ft^3

Volume of cylinder = pir^2h = pi * (6/12) ^2*3 = 3/4 pi

Thus the volume would be

24 - 3/4 pi = 21.64 ft^3.

The volume would be 21.64 ft3