SOLUTION: how to find the measure of an interior angle and an exterior angle of a regular polygon with 16 sides

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Question 694996: how to find the measure of an interior angle and an exterior angle of a regular polygon with 16 sides
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
As you go around a polygon, at each vertex, you change direction by a certain angle as you "go around the corner". That angle is an exterior angle.

When you go all the way around a polygon with n angles (and consequently n sides), you have changed your direction by a whole turn around, a total of 360%5Eo or 2pi.
If it was a regular polygon, all those exterior angles were congruent (same measure), and the measure of each was 360%5Eo%2Fn or 2pi%2Fn
For a 16-sided regular polygon, the exterior angles measure
360%5Eo%2F16=highlight%2822.5%5Eo%29 or 2pi%2F16=highlight%28pi%2F8%29

The interior angle is the "corner" you turned around. It is the supplement of the exterior angle. The measures of the interior and exterior angles add up to 180%5Eo OR pi.
In the case of your 16-sided regular polygon, the interior angles measure
180%5Eo-22.5%5Eo=highlight%28157.5%5Eo%29 or pi-pi%2F8=highlight%287pi%2F8%29

In general, the interior angle in a regular n-sided polygon measures
180%5Eo-360%5Eo%2Fn=n%2A180%5Eo%2Fn-2%2A180%5Eo%2Fn=%28n-2%29180%5Eo%2Fn or pi-2pi%2Fn=n%2Api%2Fn-2pi%2Fn=%28n-2%29pi%2Fn