Creation of this resource was inspired by this [url=http://www.gogeometry.com/school-college/5/p1411-right-triangle-incircle-excircle-tangent-isosceles.htm]problem[/url] posted by [url=https://twitter.com/gogeometry]Antonio Gutierrez[/url] (GoGeometry). [br][br]You can move any of the [b]LARGE POINTS[/b] anywhere you'd like [b]AT ANY TIME[/b]. [br][b][color=#ff00ff][br]How can we formally prove what is dynamically illustrated here?[/color][/b]