Testing season is upon us! Even though the Triangle Sum Theorem is technically a topic for Geometry, this concept shows up on a variety of state and national assessments from 5th grade all the way up to 11th grade. These notes offer a simple rules for your students regardless of grade level. Each example is explained in two different ways. "The fancy way" that requires the use of a formula and highlights the strategies used on state wide assessments. The "mental math" explanation works better for lower levels and younger students. For your students who are more intuitive about the problems, the mental math will make more sense. I always tell my students "the state testing department cannot look in your ear and see what you are thinking...so you need to write something down if you want to earn credit." At some point they should use the "fancy" method that involves writing out an equation. A matching worksheet will be uploaded soon. Please check back.

If you find these notes helpful, I would appreciate any positive feedback you would be willing to leave! Thank you and happy teaching!


Introductory Triangle Sum Theorem Cartoon Notes by Dana Burrows is licensed under a Creative Commons Attribution-NoDerivs 3.0 Unported License.