Creation of this applet was inspired by a [url=http://www.gogeometry.com/school-college/3/p1231-triangle-orthocenter-circumcenter-incenter-bisector.htm]problem[/url] posted by [url=https://twitter.com/gogeometry]Antonio Gutierrez[/url] (GoGeometry). [br][br]You can move the [b]2 LARGE VERTICES[/b] of the triangle anywhere you'd like at any time. [br][color=#1e84cc]You can alter the size of the angle with [b]BLUE VERTEX [/b]with the [b]BLUE SLIDER[/b].[/color][br][color=#bf9000]You can alter the size of the angle with [b]YELLOW VERTEX[/b] using the [b]YELLOW SLIDER[/b]. [br][br][/color][color=#ff00ff][b]How would you describe the phenomenon you see in your own words? [br][/b][/color][br][b]How can we formally prove this phenomenon to be true regardless of the locations of [color=#e69138]the orange point[/color], [color=#9900ff]the purple point[/color], and [color=#38761d]the green point[/color]? [/b]