Saturday, March 5, 2016

Triangle Inequality Theorem with Spaghetti

We were learning about the Triangle Inequality Theorem in my geometry class this past week, so I found an activity on the internet about using spaghetti noodles to do examples to prove the Triangle Inequality Theorem. The link to the activity is here, but there are many resources out there for this activity. I am going to redo and revamp the activity this summer to include some more stuff, though.

I think that students generally enjoyed the activity, and a couple of kids even stuck leftover noodles in their ear gauges, which I felt was questionable. However, as long as they did the activity, I wasn't going to make a big deal of that, and I let them have fun for a few minutes while the rest of the class finished.

Let's talk about the positives of the activity. I think that students were pretty engaged, and the directions were self-explanatory, which allowed me to circulate the room to observe students and to ask questions to extend the activity and student thinking. When I do this activity again, I want to include more examples in the activity and allow students to create their own examples and to integrate more critical thinking for increased conceptual understanding.

I am kind of tired at the moment, even though it is 8:00 on a Saturday night. So, let me wrap this up with some student photos.


  1. We do this with gridded out squares in CPM for finding the squares of side lengths to determine acute, obtuse, and right. Any time they can see the math I believe they create a memory they can retrieve later.

    1. I would love to get my hands on some CPM resources. They sound great! We don't use textbooks in our district since they cut the budget, but we are supposed to be getting Chromebooks next year. The textbooks I do have are one to two standard changes behind what we currently are required to teach, so I rarely use them. I occasionally use the teacher edition to pull problems if we need one or two to practice. I completely agree that hands-on and something tangible is best.


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