Answer:
a 1 vertical angles
2 converse of the same side interior angle theorem
Step-by-step explanation:
<1 = <3 because they are vertical angles
Vertical angles are opposite angles formed by the same lines and sharing a vertex
<2 + <3 = 180
converse of the same side interior angle theorem
If the angles on the same side between two lines add to 180, this is the same side interior angle theorem
