This application allows you to observe the properties of line segments and circles.

Drag point C to the center of the circle until it turns red and you make a central angle. Describe what you observe about the angle, intercepted arc, and sector area made by a central angle. You can use the "Angle" slider to change the angle measure.
Drag point C with the interior of the circle. Describe what you observe about the angle, intercepted arcs, and segment lengths made by two intersecting chords.
Drag point C around the circumference of the circle until it turns red and you make an inscribed angle. Describe what you observe about the angle and intercepted arc made by an inscribed angle. How is this different from a central angle?
Drag point C to the exterior of the circle. Describe what you observe about the angle, intercepted arcs, and segment lengths made by two intersecting secants.
Predict what you think the properties of the angle, intercepted arcs, and segment lengths would be if one segment was a secant and the other was a tangent.