How many sides does the polygon have if x + y = 80, In the figure below, a shaded polygon which has equal sides and equal angles is partially covered with a sheet of blank paper?

The correct answer to this question is B, nine. The figure has four sides, which means that the sum of all the angles would be 360 degrees. Being that x plus y equals 80, the sum of the other two angles would be 280. With the sum of the other two angles being 280 and those angles have equal measurements, they must be 140 degrees. In equation form, this can be solved by the following:sum of all angles' measures =180(n-2), where n = number of sides
180 (3-2)=180
180 (4-2)=360
180 (5-2)=540
180 (6-2)=720
180 (7-2)=900
180 (8-2)=1080
180 (9-2)=1260 This is done by continuously adding 180 to the sides and increasing each side by 1.