Explanation:
We start with the formulas for the volumes of a cylinder and a cone.
Cylinder:

Cone:

Now we calculate the two volumes.
Cylinder:




Cone:



The volume of the cylinder is 900pi cm^3, and the volume of the cone is 300pi cm^3.
Now we divide the volume of the cylinder by the volume of the cone.

Dividing the volume of the cylinder by the volume of the cone gives us 3, showing that the volume of the cylinder is 3 times the volume of the cone.