$$\\ \text{Volume of sphere = }\frac{4}{3}\pi r^3\\\\ \text{Volume of cone = }\frac{1}{3}\pi r^2h\\\\ \text{I'll leave you to equate the two volumes and rearrange to get h =}$$
$$\\ \text{Volume of sphere = }\frac{4}{3}\pi r^3\\\\ \text{Volume of cone = }\frac{1}{3}\pi r^2h\\\\ \text{I'll leave you to equate the two volumes and rearrange to get h =}$$