This applet is designed to give students an introduction to the properties of circle segments and lines.

What is the relationship between the radius and diameter?
A line tangent to a circle touches the circle at exactly one point. What do you notice about a radius which has this same point as an endpoint?
How can you use the Pythagorean Theorem to PROVE a line is tangent to a given circle?
What do you notice about a segment drawn through the center of the circle and perpendicular to a chord? What does it do to the chord?
What do you notice about the properties of two chords whose distance to the center of the circle are congruent?