Inverses of Power Functions Are Power Functions

Kelsey thinks that the height of any tree can be measured by the function $h(x)=\frac{1}{12}x^{3}$ where $x$ is the length in inches of any branch on a tree. She knows that the height of her tree is $320$ inches. Find the inverse of $h(x)$ and then the length of a branch on the tree. (Round to the nearest hundredth.)