What is the separation between the two massive particles, each of mass $5 \mathrm{mg}$, if they experience a gravitational force of $6.66 \mathrm{dyne}$?

The separation between the two massive particles is $5\times 10^{-9}\mathit{ m}$.
Given,
Mass of the first object, $m_1=5\mathit{ mg}$
Mass of the second object, $m_2=5\mathit{ mg}$
Gravitational force, $F=6.66\mathit{ dyne}$
In SI unit, the given data can be written as
Mass of the first object, $m_1=5\times {10}^{-6}\mathit{ kg}$
Mass of the second object, $m_2=5\times {10}^{-6}\mathit{ kg}$
Gravitational force, $F=6.66\times {10}^{-5}\mathit{ N}$
We know that the gravitational force between two particles is given by the formula:
$\mathrm{F}=\frac{{\mathrm{Gm}}_1{{\mathrm{m}}_2}^{ }}{{\mathrm{r}}^2}$
where $G$ is the universal gravitation constant, $m_1$ is the mass of the first object, $m_2$ is the mass of second object and $r$ is the distance between them.
It can also be written as
$\Rightarrow$  $\mathrm{r}=\sqrt{\frac{\mathrm{G}.{\mathrm{m}}_1{\mathrm{m}}_2}{\mathrm{F}}}$
On substituting the given values, we get
$\Rightarrow$  $\mathrm{r}=\sqrt{\frac{6.66\times {10}^{-11}\times (5\times 10{\mathrm{ }}^{-6}{)}^2}{6.66\mathrm{ }\times {10}^{-5}\mathrm{ }}}$
$\Rightarrow \mathrm{r}=5\times {10}^{-9} \mathrm{m}$