Marlene noticed that when a pair of parallel lines was cut by a transversal, two particular vertical angles were reflections of each other. what can she conclude from this observation? a. the measures of the angles must be equal. b. the angles must be complementary. c. the angles must be supplementary. d. the measures of the angles must add to 360°.

What is the next step in the given proof? choose the most logical approach. a. statement: m 1 + m 2 + 2(m 3) = 180° reason: angle addition b. statement: m 1 + m 3 = m 2 + m 3 reason: transitive property of equality c. statement: m 1 = m 2 reason: subtraction property of equality d. statement: m 1 + m 2 = m 2 + m 3 reason: substitution property of equality e. statement: 2(m 1) = m 2 + m 3 reason: substitution property of equality