## Sunday, November 16, 2014

### Parallel & Perpendicular Slope

I have always struggled getting students to really understand how to use slope to create parallel and perpendicular lines.  I have tried many things and many different activities over the years.

This year I did the typical investigation about parallel and perpendicular slopes.  It works pretty well for setting up 3 sets of parallel lines and 3 sets of perpendicular lines and asking students to analyze the equations for patterns.  This took 2 days and went pretty well.

Now on the third day I wanted them to put this new found knowledge to use.  So I created the following DESMOS graphing challenge for them.  (feel free to use and change for your use)

The challenge started pretty basic to make sure they correctly recalled the patterns for parallel and perpendicular slopes.

The next couple asked the students to start creating shapes using their patterns.

There were a couple more like this and students overall handled it pretty well.  There were a couple questions about what a parallelogram was, which I totally expected.

A few students got off to a slow start because they did not recall anything about parallel and perpendicular slopes.  This did allow me to find them quickly and re-teach the concept.  Once they could visualize the graph on DESMOS with the slopes they seemed to do much better.

A few student got off to a slow start because they did not understand what they were being asked to do.  This was partially because my projector lamp blew up and I had no way to project anything.  It was also because I threw this together quickly and I don't think it was as clear as it should have been.  I will have to tackle that next year.

Overall it worked pretty well.  We will see if this is the year where I can get students to remember perpendicular slopes!

Chris