If x is the number of sides of the regular polygon, then the sum of the interior angles is (x - 2) * 180 = 56 * 90. Solving for x gives 30 for the number of sides of the regular polygon.
To get the central angles measure, divide 360 by 30 to get 12 degrees for the measure of one of the 30 central angles.
Answer: 12 degrees
