[color=#000000]The following applet illustrates [/color][color=#1e84cc][b]Thebault's Theorem[/b][/color][color=#000000] without words, segment lengths, or angle measures. [br][br]Interact with the following applet for a few minutes. [br]Be sure to change the locations of the quadrilateral's [/color][color=#980000][b]vertices[/b][/color][color=#000000] each time before sliding the slider. [br][br]Without researching [/color][color=#1e84cc][b]Thebault's Theorem[/b][/color][color=#000000] on another tab in your internet browser, try to express this theorem in your own words as a conditional ("if-then") statement. [br][br]How could you formally prove what this applet informally illustrates? [/color]

[color=#000000][i]Creation of this applet was inspired by a [url=https://twitter.com/pickover/status/747415992653979648]tweet[/url] from Cliff Pickover. [/i][/color]