Sunday, August 5, 2012

Angle Sum Theorem

Move points A, B, and C to choose the triangle size and shape you want.  Move sliders and  to the extremer right

  This is a Java Applet created using GeoGebra from - it looks like you don't have Java installed, please go to
By Guillermo Bautista Jr. , Created with GeoGebra

  1. What do you observe about angles t, u and v
  2. What is the sum of  v, u, and t? Justify your answer. 
  3. Based on your observations above, what can you say about the sum of the interior angles of a triangle? Explain your answer. 


  1. I will learn more about this theorem. I try to keep my brain busy. Thanks!