Find the square root of
$324$

Find the square root of

$\frac{256}{289}$

Find the square root of

$\frac{441}{625}$

If the square root of $1\frac{7}{9}$ is $\frac{p}{q}$, then find $\frac{p}{q}$.

Find the square root of $1\frac{15}{49}.$