Seudónimo Seudónimo 22-01-2021 Mathematics contestada PLEASE ANSWER TODAY ASAP WILL GIVE BRAINLIEST TO FIRST TO ANSWER. Angle A and angle B are supplementary angles. What must be true about the angles? The sum of the angles is 180°. The angles were formed by two intersecting lines and are on opposite sides. The sum of the angles is 90°. The angles share a common side and vertex.