[Proofs] Can someone help me to understand these proofs in two column format?

1.) Prove that if two angles are congruent and supplementary, then they are both 90° angles. Given: Angle A = Angle B and Angle A + B = 180° Prove: Angle A and Angle B = 90°

Question

[Proofs] Can someone help me to understand these proofs in two column format?

1.) Prove that if two angles are congruent and supplementary, then they are both 90° angles. Given: Angle A = Angle B and Angle A + B = 180° Prove: Angle A and Angle B = 90°

firejay5 · Answer

I don't know if this help but here's a source: http://www.uhigh.ilstu.edu/math/sondgeroth/geom/07%20geom%20review%2003.htm