What is the measure of each interior angle in regular nonagon formula?

The formula for finding the interior angle of a regular n-gon is:

(n-2)180/n

Since we are dealing with a nonagon (9-gon): we plug 9 in for n and get:

(9-2)180/9 = 7 x 180 / 9 = 140

So the measure of each interior angle of a nonagon is 140 degrees.