#### Answer

The distance between the pair of points $\left( -2,3 \right)$ and $\left( 3,-9 \right)$ is $13$ units.

#### Work Step by Step

Consider the provided pair of points:
$\left( -2,3 \right)$ and $\left( 3,-9 \right)$
The distance $d$, between the points $\left( {{x}_{1}},{{y}_{1}} \right)$ and $\left( {{x}_{2}},{{y}_{2}} \right)$ is given by:
$d=\sqrt{{{\left( {{x}_{2}}-{{x}_{1}} \right)}^{2}}+{{\left( {{y}_{2}}-{{y}_{1}} \right)}^{2}}}$
Substitute $3$ for ${{x}_{2}}$, $-2$ for ${{x}_{1}}$, $-9$ for ${{y}_{2}}$ and $3$ for ${{y}_{1}}$ in the above formula and simplify:
$\begin{align}
& d=\sqrt{{{\left( 3-\left( -2 \right) \right)}^{2}}+{{\left( -9-3 \right)}^{2}}} \\
& =\sqrt{{{\left( 3+2 \right)}^{2}}+{{\left( -12 \right)}^{2}}} \\
& =\sqrt{25+144} \\
& =\sqrt{169}
\end{align}$
On further simplification,
$d=13$
Therefore, the distance between the pair of points $\left( -2,3 \right)$ and $\left( 3,-9 \right)$ is $13$ units.