Angles in a Circle
The vertex of an angle can appear on, inside, or outside a circle. How does the location and measure of the vertex angle compare with the measure(s) of the arc(s) it intercepts?

Related External Resources 
Circle Angles
These activities involve interactive programs whose circles can be manipulated by clicking and dragging points.
Coffee Cup Caustic [ java applet ]
This interactive demonstration shows how light rays bounce off of the side of a coffee cup.
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