# Congruent Triangles - Extra Information Activity

I really like congruent triangles.  It is one of my favorite units in Geometry.  I have lots of activities for congruent triangles and the kids are finally starting to get used to proofs.

Throughout the unit, I constantly remind my students that they need three pieces of information to show that the triangles are congruent.  I really like using this little activity to reinforce that idea.  This activity is part of my free resource library.  You can get access here.

First print all of the little matching cards.  All of the pieces look like this.

When, I copied the matching cards, I used a different color for each “problem”.  That way, I didn’t have to number the bags or worry about pieces getting lost.  It took some organizing though.  Each problem has four pieces.  So, I made sure that one of the SSS problems was light blue for all of the pieces.  When matched, the pieces look like this:

All together, I have three sets of each problem.  That way, I don’t have to have a bag of each one for every student.  They just return the bags as needed.

When the student takes a bag, they sort through the pieces.  They decide which piece of information is not needed to prove the triangles are congruent by the given theorem or postulate.  Then, they record the information on their recording sheet.

This works really well for my students.  It’s like they are working on little mini-proofs.  If you try this, I hope it works well for you!

1. Love the idea and I look forward to trying it with my students this week! How do you know which cards go together in a set though? I might be missing something, but the file doesn't specify which cards go together.

1. You are totally right, it doesn't. The top four on the first page go together, the next four go together, etc. I just put the SSS, SAS, ASA cards with them in the order they are listed on their page as well. As I'm typing this out, I can tell that it doesn't make sense at all.... I'm sorry! I'll try to get the file updated so that it makes a little more sense VERY soon!

2. I just updated the file. Hopefully, it makes more sense now. If not, send me an email :) mrseteachesmath AT gmail DOT com

2. Hey, I would really love to use this but I can't seem to get the recording sheet to open. Is there any other way I could get it?

3. DRaulie, try downloading it again. I think I fixed the problem you may be having. If you are still having trouble, send me an email at mrseteachesmath@gmail.com and I will send it to you. :)

4. Awesome! It worked. Thank you.

5. I just did this activity with my middle and high school math II students. Thank you for fixing the file, that helped A LOT. I ended up writing them out on colored index cards - they were sturdy enough and I didn't have to try to use our awful laminating machine! Some didn't quite "get it" at first, but once I worked out a problem with them and they could see my strategy, they caught on very quickly. Thank you so much for sharing!

6. I love this idea! I thought I would offer an addition to the answer sheet. I plan to make it landscape to fit one more column... both triangles for each problem where they have to mark the information from the cards they used.

7. The bitly for this activity isn't working?

1. This activity is part of my free resource library. If you haven't signed up for my free resource library, you can do so here: http://www.subscribepage.com/mrseteachesmath