#### Answer

$\dfrac{9}{5}$

#### Work Step by Step

Using the properties of radicals, the given expression, $
\sqrt{\dfrac{81}{25}}
,$ simplifies to
\begin{array}{l}\require{cancel}
\dfrac{\sqrt{81}}{\sqrt{25}}
\\\\=
\dfrac{\sqrt{(9)^2}}{\sqrt{(5)^2}}
\\\\=
\dfrac{9}{5}
\end{array}