Answer
$\sqrt{275.6}
\text{ units OR }\approx
16.601
\text{ units}$
Work Step by Step
Using the Distance Formula, $d=\sqrt{(x_1-x_2)^2+(y_1-y_2)^2}$, the distance between the given points is
\begin{array}{l}
\sqrt{(7.4-(-1.2))^2+(-8.6-5.6)^2}
\\\\=
\sqrt{73.96+201.64}
\\\\=
\sqrt{275.6}
\text{ units OR }\approx
16.601
\text{ units}
.\end{array}