What is the sum of the interior angle measure of a 13 sided polygon?
Answer It is Dodecagon. To find this, you have to first find the exterior angle of the polygon. Since the exterior angle of a polygon is always supplementary to the interior angle, you subtract the measure of the interior angle from 180. 180-150=30. Now You divide 360 by the measure of the exterior angle to get the number of sides of the polygon. 360/30=12. A 12-sided polygon is called a dodecagon