What is the size of the exterior and interior angle of a regular 13 sided polygon?

First of all select one vertex on the polygon and draw straight lines from the selected vertex to every other vertex on the polygon. In doing so this should divide the shape into 11 triangles. Using the knowledge that angles within a triangle add up to 180 degrees we can then multiply 180 degrees by the number of triangles in the shape (11). 11180=1980. Our result shows the total of all interior angles and so to find the size of a single interior angle we divide our total by the number of angles. 1980/13=152.3 degrees approx. To then calculate the exterior angle we can use our knowledge that the sum of an interior angle plus and exterior angle equates to 180. By reversing the calculation 180-152.3=27.7. Thus our interior angle = 152.3 and exterior angle =27.7. You can check this answer as the sum of all exterior angles equates to 360 degrees. 27.713=360.1.