First, students will learn why a radius is perpendicular to a chord if and only if the radius bisects the chord. Next, students will learn how to use this theorem, and the Pythagorean theorem, to find the distance from the center of a circle to a chord. Students will be given the radius or diameter of the circle, and the length of the chord, then asked for the distance from the center of the circle to the chord. For example: Find the distance from the center of a circle with a diameter of 26 in to a chord of 10 in (video). Also, students will learn how to find the radius or diameter of a circle from the length of a chord and the distance between the center of the circle and the chord. For example: In a circle, the length of a chord is 24 cm, and the distance between the center of the circle and the chord is 5 cm. Find the length of the radius (video). Finally, students will learn why two chords are congruent if and only if they're equidistant from the center (video).