Answer
3.76 cm
Work Step by Step
Coulomb’s law shows us that the magnitude of the force between charges is inversely proportional to the square of the distance between them.
If the force is found to have tripled, i.e., multiplied by a factor of 3, then the separation distance was multiplied by a factor of $\frac{1}{\sqrt3}$.
$$d_{new}=\frac{1}{\sqrt3} (6.52\times10^{-2}m)= 3.76\times10^{-2}m $$