Geometry: Common Core (15th Edition)

$m$ of an exterior angle = $14.4^{\circ}$
The measure of one of the exterior angles of a polygon is given by the formula: $\frac{360}{n}$, where $n$ is the number of sides in the polygon. We have a polygon with $25$ sides, so let's plug this information into the formula: $m$ of an exterior angle = $\frac{360}{25}$ Divide to solve: $m$ of an exterior angle = $14.4^{\circ}$