In the given figure, two wheels $$P$$ and $$Q$$ are connected by a belt $$B$$. The radius of $$P$$ is three times that of $$Q$$. In the case of the same rotational kinetic energy, the ratio of rotational inertias $$\left(\frac{I_1}{I_2}\right)$$ will be $$x : 1$$. The value of $$x$$ will be _________.