The volume of a cylinder is equal to that of a cone. The height of the cylinder is 18 cm. Its bottom area is three times that of the cone. How high is the cone?

The volume of a cylinder is equal to that of a cone. The height of the cylinder is 18 cm. Its bottom area is three times that of the cone. How high is the cone?

Cut the side of the cylinder along the height to get a rectangle. The length of the rectangle is equal to the circumference of the bottom of the cylinder, and the width is equal to the height of the cylinder, so the product of the side of the cylinder is equal to the circumference of the bottom of the cylinder