The key to this proof is that we want to show that the sum of the angles in a triangle is 180°. Therefore, a triangle's interior angles sum to 180 … Further, suppose that for any j-gon with 3

The key to this proof is that we want to show that the sum of the angles in a triangle is 180°. Therefore, a triangle's interior angles sum to 180 … Further, suppose that for any j-gon with 3