Ruler and compass constructions

Some links to websites that discuss ruler and compass constructions.

• Compass and straightedge Wikipedia article describing what can and cannot be done with ruler and compass. Includes animated illustrations of the construction of a regular pentagon and hexagon, and the explicit formula for the cosine of the angle needed to construct the heptadecagon (17-sided polygon) in terms of square roots. Has links to many other related articles including ones about trisecting an angle, doubling the cube and squaring the circle.
  
  
• GRACE - Graphical Ruler and Compass Editor A Java applet for doing ruler and compass onscreen.
  
  
• Ruler and Compass Constructions A description of the most elementary ruler and compass constructions.
  
  
• Angle trisection from Geometry Forum Liesurely discussion of the angle trisection problem including Archimedes' method (with a marked ruler) and the the Quadratrix of Hippias.
  
  
• Angle trisection from MathWorld A similar discussion with more technical details.
  
  
• Archimedes' Trisection An interactive graphic demonstration of Archimedes' method of trisection.
  
  
• All the possible polygons! YouTube video (4:48) showing ruler and compass constructions of all possible n-gons for n ≤ 51.
  
  
• Compass and straightedge - the regular Heptadecagon YouTube video (1:39) showing the ruler and compass construction set to music. Unfortunately, the aspect ratio is wrong, making the circles look like ellipses. The YouTube site has a written explanation of the construction, which is not easy to follow otherwise.