Question

The height of a cylinder is twice the radius of its base.

A cylinder has a height of 2 x and a radius of x.

What expression represents the volume of the cylinder, in cubic units?

4πx2
2πx3
πx2 + 2x
2 + πx

Answer 1

Volume = πr^2h. With r = x and h = 2x,
V = π(x^2)(2x) = 2πx^3.

So the correct expression is 2πx^3.