There is a conical part with a bottom diameter of 4 decimeters and a height of 15 decimeters. Now, it is fused into a cylinder with the same bottom as him. What is the height of the cylinder

There is a conical part with a bottom diameter of 4 decimeters and a height of 15 decimeters. Now, it is fused into a cylinder with the same bottom as him. What is the height of the cylinder

Cylinder = bottom area * height
Cone = bottom area * height * 1 / 3
Cylinder height = 15 △ 3 = 5 decimeters