1. **State the problem:** We need to solve for $h$ given the expression for the derivative: $$\frac{1}{3\pi} \times \frac{1}{2} h^2 \times h.$$ 2. **Simplify the expression:** Multiply the terms involving $h$: $$\frac{1}{3\pi} \times \frac{1}{2} h^2 \times h = \frac{1}{3\pi} \times \frac{1}{2} h^{2+1} = \frac{1}{3\pi} \times \frac{1}{2} h^3 = \frac{h^3}{6\pi}.$$ 3. **Set the derivative equal to a value:** Since the problem asks "what is $h$?" for this derivative, we assume the derivative equals some value $D$. So, $$\frac{h^3}{6\pi} = D.$$ 4. **Solve for $h$:** Multiply both sides by $6\pi$: $$h^3 = 6\pi D.$$ Take the cube root of both sides: $$h = \sqrt[3]{6\pi D}.$$ 5. **Interpretation:** To find a numerical value for $h$, you need the value of the derivative $D$. Without $D$, $h$ is expressed in terms of $D$ as above. **Final answer:** $$h = \sqrt[3]{6\pi D}.$$