Each interior angle of a regular n-gon has a measure of 140 degrees. find n?

Answer: n=9

---- Explanation:

140 degrees is the measure of each angle and the sum of the interior angle is

180(n-2)

So we have 140(n) is the sum of the n interior angles.

140n=180(n-2)

140n=180n-360

-40n=-360

n=9

Check it:

180(9-2)=1260 divide this by 9 and we have 140 as desired