The measure of an interior angle of a regular polygon is 140. Find the number of sides the polygon has.?

It has nine sides. The formula is 180(n-2)/n. This is because the polygon has n (number of sides) minus two triangles (thus 180) This is the sum of angle measures. Divide it by n, number of sides, and you have the single angle measure. Since the above equation equals 140, solve for n and you get nine.