Counterintuitive Intersection of Two Line Segments

Two towers of heights and are separated by a distance . From the top of each tower, a light beam is aimed at the base of the opposite tower. This Demonstration shows that the height of the intersection (red dot) of the two light rays does not depend on the distance separating the two towers. This result is sometimes called the "crossed ladders theorem".


  • [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.