The diagram shows a solid metal cylinder.

Question

The cylinder has base radius 2x and height 9x.
E cylinder is melted down and made into a sphere of radius r.
Find the expression for r in terms of x.

Answer 1

V = πr^2h = π(2x)^2(9x) = 4/3πr^2

This is volume of the cylinder and volume of the sphere. You can simplify this.