An interactive applet and associated web page that demonstrate the "Intersecting Chords" Theorem. (When two chords intersect each other inside a circle, the products of their segments are equal.)

The applet presents a circle with two chords. Each end of the chord can be dragged. As it being dragged a calculation continuously changes that shows that the products of their segment are in fact equal. The calculation can be turned off for class discussions.

The text on the web page gives four different formulae for calculating the area, depending on the initial givens.

Applet can be enlarged to full screen size for use with a classroom projector. After use in the classroom, student can access it again from any web browser at home or in the library with no login required.

This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.