Question

Find the sum of the interior angles of an octagon.

Answer 1

The sum of the interior angles of a polygon $=(2n-4)\times {90}^{\circ }$
Here $n=8$
The sum of the interior angles $=(2\times 8-4)\times {90}^{\circ }$
$=(16-4)\times {90}^{\circ }$
$=12\times {90}^{\circ }={1080}^{\circ }$