[color=#000000]Any [/color][color=#980000][b]quadrilateral that is inscribed inside a circle[/b][/color][color=#000000] is said to be a [/color][i][color=#980000][b]cyclic quadrilateral[/b][/color][color=#000000].[/color][/i][color=#000000] [br][br]In the applet below, a cyclic quadrilateral (with moveable vertices) is shown. [br][br]Slide the slider slowly and carefully observe what happens. Then, reset the applet. [br]Change the locations of the BIG POINTS and repeat this process.[br][br]Repeat the previous steps a few more times. Then, answer the questions that follow. [/color]
Suppose, in the applet above, the [b][color=#980000]brown angle measures 76 degrees.[/color][/b] [b][color=#1e84cc]What would the measure of the blue angle be? [/color][/b]
Suppose, in the applet above, [b][color=#ff00ff]the pink angle measures 130 degrees. [/color][/b] [b][color=#38761d]What would the measure of the green angle be? [/color][/b]
From what you've observed, how would you describe the relationship between any pair of opposite angles of a cyclic quadrilateral?
Note that all 4 of this cyclic quadrilateral's interior angles are [b][i]inscribed angles[/i] of a circle.[/b] How does the measure of an inscribed angle compare with the measure of the arc (of the circle) it intercepts?
If you need a hint answering this question, [url=https://www.geogebra.org/m/UdXwSHVj]click here[/url].
Explain why, using your response for (4) above, the phenomena you've observed above holds true [b]for any cyclic quadrilateral. [/b]