How I Teach Parallel Lines Converse Theorems

Parallel Lines Converse Theorems can be such a hard topic for students.  In my opinion, this is really the first time that students really have to pick apart a diagram and visualize what’s going on.

These teaching tips will help high school geometry students understand parallel lines proofs.  I love to use this free activity before I start the lesson (class notes).

When I start the lesson, I hand each student two cards.  One card says “the lines are parallel” the other says “corresponding angles are congruent” (or alternate interior, alternate exterior, same-side interior).  I tell the students to “put the cards in order to make a theorem”.  This takes them all of 2 seconds.  

How I Teach Parallel Lines Converse Theorems

Then, I remind them of what a converse is.  I have them switch the cards.  We talk about what is different.  This intro takes me less than 5 minutes, but it helps some of the kids a little.

How I Teach Parallel Lines Converse Theorems

Then, I usually use guided notes.  I’m not in love with the notes I use currently.  I would like to use some sort of foldable instead.  More and more I’m wanting to take the plunge into interactive notebooks.

After the lesson, I use this powerpoint.  It’s not fancy at all, but it gets the job done.  First, I project the slide onto the whiteboard.  
How I Teach Parallel Lines Converse Theorems
Then, I outline the angles in the question with a marker.  When you hit enter to move to the next slide, all of the unnecessary lines disappear.  Only the parallel lines are left for the students to see.  There are a bunch of problems for the students to practice.  I spend as much time as I can on this, because I think it really helps my students.  Even on tests, I can see where students outlined the angles to see which lines are parallel.

These teaching tips will help high school geometry students understand parallel lines proofs.  I love to use this free activity before I start the lesson (class notes).

What do you do to help your students with this challenging topic?