1st May, 2012: How do we use secant, chord, and tangent ratios in circles?

A secant in a circle is a straight line that intersects a curve at two or more points

A chord is a line segment on the interior of a circle with both points lying on the circle

Two chords intersect inside a circle. Segment A X segment B= segment C X segment D

If two secant segments intersect outside a circle, then the product of the secant segment with it's external portion equals he product if the other secant segments with it's external portion.