From Slant to Volume

A cone is often described by its radius and its slant height, because those are the easy lengths to measure on a real one. The volume still needs the true height, so find it first.

This cone has radius 8 and slant height 17. Step one, the height: ${h}^{2} = {17}^{2}-{8}^{2} = 225$, so h = 15. Step two, the volume: $\frac{1}{3}\cdot \pi\cdot {8}^{2}\cdot 15 = 320\cdot \pi$.

On the figure the height has no label. Tap it and pick Slant height to put its value in. Then the cone's volume has everything it needs.