Answer
$3\sqrt{5}$
Work Step by Step
Getting the perfect factors and then extracting its root, the simplified form of the given expression, $
\sqrt{45}
,$ is
\begin{array}{l}\require{cancel}
\sqrt{9\cdot5}
\\\\=
\sqrt{(3)^2\cdot5}
\\\\=
3\sqrt{5}
.\end{array}
