Question 1124435
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From your post,  it is unclear what the angles 1, 2, 3 and 4  are; unclear how they are inter-related and how they relate to the segments.


So,  at given conditions I can not help you.



But I can do better:  I will give you the reference to the lesson,  where you will find a lot of interesting facts and proofs 
related to angles at parallel lines and transverse lines :


&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/Angles/Angles-basics.lesson>Angles basics</A> 

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/Angles/Vertical-Angles-.lesson>Vertical angles</A> 

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/Angles/Parallel-lines.lesson>Parallel lines</A> (*)

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/word/geometry/How-to-solve-problems-on-suppl-compl-or-vertical-angles-Examples.lesson>HOW TO solve problems on supplementary, complementary or vertical angles - Examples</A>

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/word/geometry/How-to-solve-problems-on-parallel-lines-Examples.lesson>HOW TO solve problems on parallel lines - Examples</A> (**)

in this site.


These lessons are &nbsp;(*)&nbsp;  and &nbsp;(**)&nbsp; of the list.



And one more hint: &nbsp;start writing the proof without using &nbsp;"the two column format".