Sunday, October 7, 2012

Angle Pairs


This past week my sophomore class was working on angle relationships.  I wanted something that went beyond the definitions because many of my kids could tell you that complementary angles add up to 90 degrees, but then have trouble turning that into an actual equation.

This was an attempt to make something that was more useable than a definition.  The kids started by cutting out the first six card fronts and attaching them to index cards.

Next we went through them card by card labeling and coloring the angles, writing the relationship in words, and then writing an equation.

After going through all of them, I gave the kids the six card backs.  They had to look at each one and decide which relationship it showed and tape it to the right card.  They needed have me or someone with the correct answers check their cards before actually taping.

Here is a kid matching up his cards
After putting the problems on, we went through the problems and discussed how to use what we knew to write and solve an equation.  Going through this took very different amounts of time in different periods of mine.


After creating the cards, we are now using them to solve problems.  On Friday I had them work on this worksheet:
Get the whole worksheet here

Before solving anything, I had them go through the entire front of the worksheet just labeling each problem with either: complementary, supplementary, vertical, or none.  I had them take out their complementary, supplementary, and vertical cards to use as a references.  I was really impressed with how well this worked.  They looked at the problem and then compared it to their cards to help make a decision.

The first 8 problems were just naming the angles, but the rest involved solving for variables.  Even when the directions didn't say to, I said that they needed to first write down what angle pair was being shown.  This is a habit I want them to get into because often kids look at problems like this and just completely blank out on what to do.  This way it at least gives them a starting point to the problem.

This is a kid using his cards to work on the activity.

For the second part of this we'll be doing the same thing with the angles formed by parallel lines and transversals.  Before working on this, I'm going to have them create a card for consecutive interior angles.  We did a quick coloring activity on Friday that you can kinda see in the picture above.  Just an easy visual to show which angles are congruent and that the two angles will add up to 180 degrees.  The consecutive interiors card will be nice to build on this a little bit and to help for the next activity.  

Get the whole worksheet here

For any kids that had trouble classifying the angle pair being shown, I had them color in the two angles we were looking at and it really helped them to compare the example to their cards.  This activity was lengthy because I didn't want to rush it.  We created the cards over a number of days because I wanted to make sure that the kids got down all the correct information so that they can now use the cards.  I also wanted to make sure to give them the time to really think things through on their own (like matching the back of the cards and classifying and coloring angles) so I really took time on it.

I felt like they were really using the cards on Friday to solve the problems so I was happy with that. During the course of this we also went through how to set up and solve two step equations so I also liked that I was able to sneak that in and now I won't really have to go over it too much later.


  1. Hi Sarah! Great post! I am a new teacher (trained in language arts, but teaching in all subjects--eek!), and am trying to find resources to teach math to my (struggling) students. I love this lesson, and was trying to print out the flashcards, but it wants me to pay money (even though it says they're free...). Any suggestions? I think maybe I'm doing something wrong.

    Thank you!
    Gina Hundt

  2. Sarah
    Thank you for such a a complete resource on ISNs. I started having my HS geometry students create foldables second semester this year in hopes of salvaging my unsuccessful attempt at having students create a journal. The foldables have been INCREDIBLY successful; the journals are better but not what I now know I want...ISNs like yours! I've been researching and yout blog is by far the most helpful. So my plan is to conyonue to use foldables and create ISN next year. I did not see the back side of the amgle pairs flashcards, did I miss them or are they missing? Again thanks so much for sharing and helping a 20+ year veteran try new ideas!
    Michele Ratcliff

  3. This looks like such a wonderful idea! (I want to see specifics but the site says that it was deleted... would it be possible for you to post a document or file in which I can clearly see what was on the flashcards themselves??)

  4. Hi. I created a second page of angle pair types to as closely match what you did as possible. Here it is. Hope you find it helpful, and that I haven't offended you. Thank you.

  5. This is a great idea. I will try this activity with my classes!

  6. I really like this idea! I would prefer to represent supplementary angles not as a linear pair. I'm careful to distinguish the two as students sometimes think they're one and the same.

  7. Is there a link to the flashcards,... I love the sounds of this activity and would like to use it in my geometry class next year. I just found your blog and have spent all day getting ideas! Thank you so much for sharing.

  8. Is there a chance of see exactly what you wrote on the flashcards?

  9. Thanks for sharing.This is a great idea!

  10. Is there a link to the flashcards? I would love to use it! Thanks for sharing!

  11. I have to now integrate Geometry into my Algebra 1 classes. Eeekk, freaking out a little. I am teaching my first unit next week. I love these flashcards. Is there a link I can use to print them off? I didn't see it.