The Nonagon

The Nonagon (9 sided polygon) is also a figure impossible to construct with only compass and straightedge. It can, however, be approximated.

  1. Draw circle O.
  2. Draw AB, the diameter of circle O.
  3. Divide AB into 9 parts.
  4. Draw a circle at A and B, each with radius AB. They cross each other at C.
  5. Find D, the second point from the left on AB.
  6. Draw a line through points C and D.
  7. CD crosses circle O at point E. Points A and E are points of the nonagon. Use them to find the rest!

© Apr.7 2003 Robin Hu. All Rights Reserved.