Complete the two-column proof for the theorem "If two angles are congruent, then their supplements are congruent." (Pick one of these bellow for each number)
2. complement or supplement

3. definition of the supplement of an angle, definition of the complement of an angle, or substitution property of equality

4. m m
5. Substitution Property of Transitivity, Equality, or Congruence

6. Substitution Property of Equality, Definition of the supplement of an angle, Addition Property of Equality

7.