Explanation:
<1 and < 7 are alternate exterior angles
Alternate exterior angles are equal
Hence, < 1 and <7 are congruent
<6 and <3 are interior angles on the same side of the transversal
Interior angles on the same side of the transversal are supplementary angles
Hence, <6 and <3 are supplementary.
<1 and <3 are vertical angles
Vertical angles are equal
Hence, <1 and <3 are congruent
<7 and <3 is neither congruent nor supplementary
,<7 and <3 are complementary angles