What geometry theorem is dynamically being illustrated in the applet below?[br][color=#1e84cc]Note: The ray that looks tangent to the circle [i]is[/i] tangent to the circle. [/color] [br](Feel free to move any of the points anywhere you'd like.)
[color=#000000][b]Theorem:[/b][/color][br]In a circle, the [color=#ff00ff][b]measure of an angle[/b][/color] formed by a [color=#1e84cc][b]chord [/b][/color]and a [color=#1e84cc][b]tangent[/b][/color] is equal the [color=#ff00ff][b]measure of any inscribed angle[/b][/color] that intercepts the [color=#ff00ff][b]same arc[/b][/color]. Since this is so, we can say that the [color=#ff00ff][b]measure of an angle[/b][/color] formed by a [b][color=#1e84cc]chord[/color][/b] and a [color=#1e84cc][b]tangent[/b][/color] is equal to [color=#ff00ff][b]half the measure of the arc it intercepts. [/b][/color]