Question

What is the measure of each angle of a regular 18-gon? If necessary, round to the nearest tenth.

Answer 1

For a regular n-gon each interior angle = 180*(n−2)/n. For n = 18:

Interior angle = 180*(18−2)/18 = 180*(16/18) = 160°

(Exterior angle = 360/18 = 20°.)

So each interior angle is 160.0°.