Someone

provide reasons for the statements.
given: ∠1 and ∠3 are vertical angles.
prove: ∠1 ≅ ∠3 .

statement reason
1. ∠1 and ∠3 are vertical angles : given

2. ∠1 and ∠2 form a linear pair.
∠2 and ∠3 form a linear pair.: definition of linear pair

3. ∠1 and ∠2 are supplementary.
∠2 and ∠3 are supplementary. :

4. m∠1 + m∠2 = 180˚
m∠2 + m∠3 = 180˚ :

5. m∠1 + m∠2 = m∠2 + m∠3:

6. m∠1 = m∠3 :

7. ∠1 ≅ ∠3 :