The sum of the interior angle measures in a regular polygon is 1800°. What is the measure of one of the interior angles of the polygon?
180(n-2) = 1800
n-2 = 10
n = 12
each interior angle = 1800/12 = 150°
or ...
each exterior angle of the 12-gon = 360/12 = 30°
which would make the interior angle 180-30 or 150°