Creation of this applet was inspired by a problem presented by Roberto Soto & Armando Martinez-Cruz (California State University, Fullerton) at their NCTM talk, "GeoGebra + GoFormative for Problem Solving, Problem Posing, and Assessment" (April 27, 2018). [br][br]You can move any of the [b]LARGE WHITE POINTS[/b] anywhere you'd like [b]AT ANY TIME.[/b][br][b][color=#ff00ff]You can also control the size of the (soon-to-appear) angle with pink vertex by using the pink slider. [br][/color][/b][br][b]How would you describe what you seen in your own words? [br][/b][br][b][color=#ff00ff]How can we formally prove what is dynamically illustrated here? [/color][/b]