Use the proof to answer the question.
given: ∠a and ∠b are supplementary angles.
∠b and ∠c are supplementary angles.
prove: ∠a ≅ ∠c
statements reasons
1 ∠a and ∠b are supplementary angles. ∠b and ∠c are supplementary angles. given
2 m∠a+m∠b=°
m∠b+m∠c=° definition of supplementary angles
3 m∠a+m∠b=m∠b+m∠c substitution property of equality
4 m∠a=m∠c subtraction property of equality
5 ∠a ≅ ∠c if two angles have the same measure, then they are congruent.
what is the value for both blanks in statement 2?
enter your answer as the value that correctly fills in the blanks, like this: 42