To me this is circular reasoning, and therefore not valid. if x is equal to y, then l is parallel to m. So that we can go either way. The following facts help in finding the unknown angles. When any two parallel lines are cut by a transversal they acquire some properties. if(vidDefer[i].getAttribute('data-src')) { When parallel lines are cut by a transversal, four types of angles are formed. I did not get Corresponding Angles 2 (exercise). You can use the following theorems to prove that lines are parallel. ( 4 votes) Show more. Direct link to AgentRaindrop's post If two parallel lines are. In this critical geometry lesson, youll learn all about parallel lines cut by a transversal. Literally wish I had this when I first started dividing with fractions. Students must not only solve for variables, but find angle measures as well. for (var i=0; i