We have a polygon whose the sum of interior angles is 20 right angles (the measurement of each right angle is 90°), that means the sum = 20 × 90° the sum = 1800°
The sum of interior angles on any polygon could be determined using formula sum = (n - 2) × 180° n stands for the number of sides the polygon has
sum = (n - 2) × 180° 1800° = (n - 2) × 180° 1800°/180° = n - 2 10 = n - 2 n = 12
