The Decagon

Constructing a Decagon (10 sided polygon) is exactly the same as constructing a Pentagon. Simply bisect one of the sides of a pentagon, and you get a decagon.
  1. Draw circle O. Find points A and B on circle O, so that OA _|_ OB.
  2. Find M, the midpoint of OB. Draw a circle at M, crossing A. Circle M crosses OB at C and crosses OA at D.
  3. Draw a circle at A, crossing C. Circle A crosses circle O at points E and F.
  4. Points E, A, F, and D are points of the decagon. Use them to find the rest!
© Apr.7 2003 Robin Hu. All Rights Reserved.