Tuesday, January 5, 2016

Intro to Angles in Degrees and Radians

Yesterday, I started a new chapter with my Pre-Calculus students and we were to talk about angles in standard position, negative angles, and coterminal angles - all in both degrees and radians. At the suggestion of a colleague, we decided to change the order we've talked about things in the past.

We used to intro it all together (degrees and radians) and on a bit of a whim, yesterday morning, we decided to intro the major concepts using degrees only, then do an activity to have students more clearly understand what a radian really is, then connect the ideas to radians.

It wasn't SUPER exciting, but it went SUPER well.

Link to my documents (I changed the blank file to a PDF, but if you want the Smart Notebook file, just let me know!) here. (Both the blank and completed notes are there)

What I might change:

  • The smaller the students made their circles in the activity, the less accurate their measurements were. 
  • Also -- I needed to tell them to mark their center (otherwise measuring the radius was quite difficult.)
  • The second time around was SO much better. Since their measurements for the angle were all near 58 degrees, I thought it would be a good idea to find the degree measure of 1 radian...I didn't think to do that in the first class. 
  • I think it would have also been beneficial to talk about the quadrantal angles in terms of radians at this point. When we talked about a full revolution being 2pi, it would have been a good time to hit the others. Next time! 
  • As a note...we shared out their info after the activity and talked about its significance. Was it likely that we all had drawn the same circle? It was a short but important conversation!
Overall, it was nothing fancy, but it went well. I'm trying to take Kate Nowak's lead and post some of the good, but possibly more boring stuff too! (Wish I would have taken pictures! I need to get more in the habit of this!) 


  1. Thanks for sharing a work in progress! Much appreciated.

  2. Hi - I really like your Unit Circle lesson, and would love to use it with my class but I would like to change the degree measures to radians on the handouts. Would you mind sharing an editable version?