# Investigating the Triangle Angle Sum Theorem

- Author:
- Ismail Khalil

To Investigate: Click and drag the vertices of the triangle and use the sliders to rotate the vertices.
Complete the activities below.

1) Hit the Reset Construction button (in upper right hand corner).
2) Click and drag the vertices to create 3 types of triangles: an acute, an obtuse, and a right triangle.
3) Record the interior angle measures of the triangle for each case.
4) Write an equation relating the 3 interior angle measures for each case.
5) What do you observe about the triangle's three interior angles when the sliders are set to 180?
6) Does the Triangle Angle Sum Theorem hold true for each case? Be prepared to explain your answer.