Help!! Angle ABC and Angle DBC are adjacent angles.
What equation must always be TRUE?*
A. Angle ABC = Angle DBC
B. Angle ABC + Angle DBC = 90°
C. Angle ABC + Angle DBC = 180°
D. Angle ABC + Angle DBC = Angle ABD

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