Saturday, April 05, 2014

Triangle exploration lesson

          This week we started our triangle exploration unit. Students were given a Tupperware that contained enough snap cubes to form lengths of 2, 3, 4, 5, 6, 8 and 10. Starting with the three shortest lengths, 2 ,3 and 4 the partners formed a triangle, if possible, using the cubes. If the lengths formed a triangle they decided what type of angle was the largest angle. They also found that some of the lengths did not form triangles.

These students found the lengths they chose formed an obtuse triangle.

These students formed a right triangle.

     As they worked they filled a sheet to to collect their information. Then looking at the sides that did not form triangles they wrote why they thought they didn't form triangles. There were some interesting observations like: "It just doesn't fit.", "It won't close.", and "they aren't long enough." It was a great visual for the students. On day two when we discussed this we actually lined the two shorter sides next to the longer side to show they were not greater than the third side. We also looked at  sides that did form triangle and the two shorter sides were longer than the third side.They kids did a great job on this activity. Of course, you know they did want to start building towers. I do need to find a building towers activity because they would love it. Suggestions anyone? 

       Click here to get a copy of the Triangle investigation sheets. This is adapted from
                           Alexander Sabatino, Jr's Picking Pythagorus Lesson.

     Everything went well until "that class" came in. I don't know if you have one of these but I have one this year. They are challenging in every area you can imagine, yet I keep trying to do group work with them. What's the matter with me? Well anyway, one of the students came in, let's call him  "T" and he quickly grabs the Tupperware and says he will pass them out. Before I can utter a word, he has eight Tupperware stacked in his arms and yes, you guessed it, he dropped them. All the snap cubes, 100's of them are all over the floor. At least "T" was busy for awhile picking them all up. Oh the joys of middle school.
     This lesson worked well  and the kids enjoyed it. It gave them an great visual for the triangle inequality rule. I will definitely be doing this again next year.
                                                           Til next time,


  1. About building towers, on the lastnday of school before the geometry final exam we built towers using the student workbooks and some newspaper to complement it, plus masking tape. The students worked in groups of 4 and had to build the tallest tower with just the workbooks and tape, no other materials. Great fun! And stress release before a test, it was so nice seeing how different all the towers turned out. Sorry, this was long ago, forgot to take puctures, long before social media but hopefully you get the "picture".

  2. Thank you Irma, this is a great idea. We don't have workbooks but I certainly have lots and lots of paper. I will do this at the end of the school year when we are cleaning out our folders. I'll post pictures for you:)


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