Triangle Angle Sum Proof

Move the vertices of the triangle and move sliders P and Q to the extreme right. What do you observe?




















This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com


Based on your observations, make a conjecture about the angle sum of a triangle.

There is a tutorial here on how to create the applet above.