Answer
$\color{blue}{\dfrac{gh^2\sqrt{ghr}}{r^2}}$
Work Step by Step
Rationalize the denominator by multiplying $r$ to both the numerator and denominator of the radicand to obtain:
$=\sqrt{\dfrac{g^3h^5(r)}{r^3(r)}}
\\=\sqrt{\dfrac{g^3h^5(r)}{r^4}}
\\=\sqrt{\dfrac{g^3h^5(r)}{(r^2)^2}}$
Bring out the square root of the denominator to obtain:
$\\=\dfrac{\sqrt{g^3h^5r}}{r^2}$
Factor the radicand such that at least one factor is a perfect square to obtain:
$\\=\dfrac{\sqrt{(g^2h^4)(ghr)}}{r^2}
\\=\dfrac{\sqrt{(gh^2)^2(ghr)}}{r^2}$
Bring out the square root of the perfect square factor/s of the numerator to obtain:
$\\=\color{blue}{\dfrac{gh^2\sqrt{ghr}}{r^2}}$