Proof for angle rules (Needing help to prove m∠3 + m∠13 = 180)

[juliak]

Needing help to prove m∠3 + m∠13 = 180
What would be the property I use? See attachment for photo of problem.

 

[tkhunny]

Look up "Alternate Interior Angles" and "Vertical Angles".

 

[Deleted member 4993]

Needing help to prove m∠3 + m∠13 = 180
What would be the property I use? See attachment for photo of problem.

You will need to use the angle theorems associated with parallel lines.

Do you know those?

If not - google it!