Surface area and volume — practice question

For a sphere, the volume is $\frac{4}{3}\pi r^3$. For a cone, the volume is $\frac{1}{3}\pi r^2 h$. A cone is taken away from a solid wooden hemisphere with radius $3\text{ cm}$. The cone also has radius $3\text{ cm}$ and height $2\text{ cm}$. The volume of the wood left is $k\pi \text{ cm}^3$.