[color=#000000]In the applet below, quadrilateral [i]ABCD[/i] has been designed so that [/color][color=#6aa84f][b]angle [i]A[/i] and angle [i]C always [/i]remain congruent. [/b](In fact, you can adjust the measures of these angles using the slider in the top left corner.) [/color][b][color=#6aa84f][br][br][br][/color][color=#980000]Directions: [/color][color=#6aa84f][br][br][/color][/b][color=#000000]1) Move any of the [b]BIG POINTS[/b] around so that [/color][color=#cc0000][b]angle [i]B[/i] and angle [i]D[/i] become congruent.[/b][/color][color=#000000] [br][br]2) If this is the case, what special kind of quadrilateral do you have? [br][br]3) Use the tools of GeoGebra to prove your response to (2) is true. [br][br]4) Again, use the tools of GeoGebra to prove your response to (2) is true. [br] This time, use a manner different from the one you used in (3) above. [/color]