Triangle Inequality Task
Click on the image to view the GSP app for this task.
triangle_inequality_ws.pdf |
My task work:
Comments:
While I saw benefit to this activity as it allowed students to often see the relationship of the triangle inequality, I think due to one side being stationary, students would have to alter sides with the same values. For example on #6, the student can clearly see why the triangle cannot be made, but cannot see the relationship of how one side is longer than two sides added up. To see this, the student would also need to look at where A = 2, B = 4, and C=7 (where A is red, B is blue, and C is green.
I also had issues with getting the sliders to the correct integer value. If you can fix the sliders to jump by a unit measure of 0.5, this task would be easier to work with.
I also had issues with getting the sliders to the correct integer value. If you can fix the sliders to jump by a unit measure of 0.5, this task would be easier to work with.
After viewing students using the lesson, it is very clear that knowing the theorem already helped to perform the activity and see the correct conjecture in the activity. Students unfamiliar could use their senses to arrive at the correct answers, but they did not see why those answers were correct. I think the students tended to see two sides and rigid and only worked with moving one side. While in most cases, this led to the correct answer, the inability to play with both sides and move them around led to issues. Perhaps showing the lengths of the smaller sides added up visually would have helped arrived there. I know that I saw if I lined the two shortest sides up and swing the longest side around 360 degrees I could see that sometimes it was impossible for them to meet, and thus I knew I could not form a triangle, but this thought process is advanced for discovery and conjecture (and involves already knowing the conjecture). I'd have to play around with this to understad how to make the lesson more valuable to producing the objective.