PLZ HELP WITH THIS MATH 20 POINTS

Provide the reasons for this proof .
Given:Line m is parallel to line n.
Prove: <1 is supplementary to <3.

Here is the picture of the full problem.

PLZ HELP WITH THIS MATH 20 POINTS Provide the reasons for this proof GivenLine m is parallel to line n Prove lt1 is supplementary to lt3 Here is the picture of class=