5. Complete the proof. Given: m/1 + m/2 = 90 Prove: m/3 = 90 3 21 = 23 the sum of 21 and 22 m/3 = 90 21 23 forms a vertical angle pair with 1 m/1 + m/2 = m/3 So because vertical angles are congruent. Since m/1 + m/2 = 90 is given, by the transitive property of equality. 2