# What is a Conical Frustum?

**Geometry**Level 3

Imagine an perfect hourglass that has a base radius \(R_1\) and a height \(Z\) from base to center. A solid ball with a radius of \(R_2\) is stuck perfectly within the middle of the hourglass (it leaves no gaps). The hourglass is filled completely with sand on both sides of the hourglass. Given that

- \(Z = \dfrac {3}{R_1R_2\pi} \text{ cm}\).
- \(R_1+R_2 = 9\sqrt {R_1R_2}\text{ cm}\).
- The volume of the sand is \(120\text{ cm}^3\).

Find the volume of the ball.

**Note**: Image drawn not up to scale.