Poncelet's Porism for Quadrilaterals

Assume circle contains circle . If it is possible to inscribe a quadrilateral touching with its vertices and with its sides, then it is always possible to find a quadrilateral touching both circles and passing through any point of outside . Such quadrilaterals are called bicentric. For this Demonstration circle (in tan) is fixed and the position of circle (in brown) can be changed by dragging the red center (the radius of is obtained through Fuss's formula). You can change the position of the red vertex of the quadrilateral.

SNAPSHOTS

  • [Snapshot]
  • [Snapshot]
  • [Snapshot]
    • Share:

Embed Interactive Demonstration New!

Just copy and paste this snippet of JavaScript code into your website or blog to put the live Demonstration on your site. More details »

Files require Wolfram CDF Player or Mathematica.