Illuminations: Power of a Point

Power of a Point
Use this tool to investigate what happens when point P is moved to various points within, on, and outside the circle. What, if any, relationships can you identify among the segments and radius?

Instructions
 
Dragging point G will change the size of the circle, dragging P will move the point of intersection, and dragging A and  C will change the location of the chords.

The Show Radius button highlights the radius in the drawing and displays the length of radius FG. The Show Products button displays the value of two products, AP × BP and CP × DP.

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NCTM Resources

Principles and Standards for School Mathematics

Lessons
National Council of Teachers of Mathematics Thinkfinity
More and Better Mathematics for All Students
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