Complete the proof....

Answer:
The correct options are;
1. Definition of supplementary angles
2. m∠1 + m∠2 = m∠1 + m∠3
3. m∠2 = m∠3
4. Definition of Congruent Angles
Step-by-step explanation:
The two column proof is presented as follows;
Statement [tex]{}[/tex] Reason
1. ∠1 and ∠2 are supplementary [tex]{}[/tex] Given
[tex]{}[/tex] ∠1 and ∠3 are supplementary
2. m∠1 + m∠2 = 180° [tex]{}[/tex] Definition of supplementary angles
[tex]{}[/tex] m∠1 + m∠3 = 180°
3. m∠1 + m∠2 = m∠1 + m∠3 [tex]{}[/tex] Transitive Property
4. m∠2 = m∠3 [tex]{}[/tex] Subtraction Property of Equality
5. ∠2 ≅ ∠3 [tex]{}[/tex] Definition of Congruent Angles
Given that angles ∠1 and ∠2 are supplementary angles and angles ∠1 and ∠3 are are also supplementary angles, then the sums of m∠1 + m∠2 and m∠1 + m∠3 are equal, therefore, ∠2 and ∠3 have equal quantitative value and therefore ∠2 = ∠3 and by definition, ∠2 ≅ ∠3.