Google Classroom
GeoGebraGeoGebra Classroom

GoGeometry Action 91!

Creation of this applet was inspired by a problem posted by Antonio Gutierrez (GoGeometry). You can change the size of the interior angle with purple vertex by using the purple slider. Feel free to place any of the triangle's vertices where you'd like at any time. How can we formally prove what is dynamically illustrated here?

Quick (Silent) Demo