Question 398123
The sum of the interior angles is {{{180(n-2)}}} since you can draw n-2 non-overlapping triangles within the polygon.


The sum of all the interior and exterior angles is simply {{{180n}}}. If we subtract the total sum of the interior angles, we get {{{180n - 180(n-2)}}}, or 360 degrees.


Not enough information for the third one, but the average measure is also the measure of an angle of a regular n-gon, or {{{180(n-2)/n}}}.