The radius of a cylinder is 4 cm and the height is 9cm what's the area of base and the volume?

The area of the base is a circle, so you would use the area of a circle equation which is pi (r) ^2 to find the area of the base. Plug in 4 into r, because this is the radius given.

To solve for the volume, the equation for volume of a cylinder is (area of base) x (height). So in those case, (pi) (r) ^2 x 9.