Answer
$m$ of the interior angles in a decagon = $1440^{\circ}$
Work Step by Step
According to the Polygon Angle-Sum Theorem, the sum of all the measures of the interior angles of a polygon is $(n - 2)180$, where $n$ is the number of sides of the polygon.
A decagon has $10$ sides.
$m$ of the interior angles in a decagon = $(10 - 2)180$
$m$ of the interior angles in a decagon = $(8)180$
Multiply to solve:
$m$ of the interior angles in a decagon = $1440^{\circ}$
