#### Answer

$c=39 \text{ } m$

#### Work Step by Step

Using $a^2+b^2=c^2$ or the Pythagorean Theorem, then,
\begin{array}{l}\require{cancel}
15^2+36^2=c^2
\\\\
225+1296=c^2
\\\\
1521=c^2
\\\\
c=\pm\sqrt{1521}
\\\\
c=\pm\sqrt{(39)^2}
\\\\
c=\pm39
.\end{array}
Since there are no negative measurements, then $
c=39 \text{ } m
.$