30.10. The integer $x$ is the least among three positive integers whose product is 2160 . Find the largest possible value of $x$.
30.10. 10
Note that $2160=2^{4} \cdot 3^{3} \cdot 5$. By trial-and-error method, we will notice that the set of three positive integers whose product is 2160 that will have a maximum least integer is $\{10,12,18\}$.