GoGeometry Action 178!

Creation of this resource was inspired by a [url=http://www.gogeometry.com/school-college/3/p1276-equilateral-triangle-internally-tangent-circle-tutoring.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][br]How can we formally prove what is dynamically illustrated here? [br][br]
Quick (Silent) Demo

Information: GoGeometry Action 178!