Tuesday, February 12, 2013

Day 94: SAS Congruence

My original plan here was to have everyone use half of the "bundle" we used yesterday - the long straw, the middle straw, and the class would agree on an angle. You can then set the two sides to the given angle with the pipe cleaner, and trace out what you've created. Then, complete the triangle by drawing in the 3rd side. Once the triangle is complete, measure EVERYTHING you don't already know (3rd side and two angles). Idea being that if everyone started with two congruent sides and a congruent included angle, everyone should end up with the same (congruent) triangles. 


  • Holding the created angle steady while tracing was problematic
  • Students are not very skilled with either the ruler or the protractor
  • Some students trace the inside of the angle, some the outside
Overall, the conclusion comes across, but it might help to encourage rounding to the nearest cm to avoid measurement errors clouding the idea. 

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