The formula for finding the sum of the interior angles in a polygon is expressed as
Sum = 180(n - 2)
where
n is the number of sides in the polygon
From the information given,
n = 20
Thus, the sum of angles in this polygon is
Sum = 180(20 - 2) = 180 * 18 = 3240
Since the polygon is regular, it means that all the angles are equal. Thus,
Measure of each angle = 3240/20 = 162 degrees