What is the measure of each interior angle of a regular polygon?

It's not really specific when you say "polygon" but here we go! To even find the Measure of an interior angle for a regular polygon we need this formula: n (n being the number of sides) multiplied by 180 subtracted by 360 divided by n. This gives your the reg int angle. Starting with Triangle, here are the list of interior angles for every polygon up to 10 (for as after 10 there aren't anymore names it's just n-gon example: 11-gon)

Triangle = 60 degrees

Quadrilateral = 90 degrees

Pentagon = 108 degrees

Hexagon = 120 degrees

Heptagon = 128.6 degrees

Octagon = 135 degrees

Nonagon = 140 degrees

Decagon = 144 degrees

11-gon = 11 X 180 - 360 divided by 11 = 147.2 degrees (Hmmm, not quite sure about that one, mate.)

You might have to ask someone else about this, too, for I think there is a certain limit on which an n-gon can be measured in an regular int angle. Something like 180, I believe.