
Re: Pentagon with a sraight edge and compass
Posted:
Sep 2, 1998 3:04 PM


On 2 Sep 1998, Charlie Mead wrote:
> I would love to have this information. At one timeI knew > how to do this, but I have forgotten.
Here's what I call the "BISECTBISECT" construction, which is one of the simplest. I suppose that you want to draw your pentagon ABCDE in the circle with center O whose Northernmost, Southernmost, Easternmost and Westernmost points are NSEW, with one vertex being at E:
N  A B    Y    \    \ WZOXE          C    D S What you do is BISECT the segment NO at Y, and then BISECT the angle OYE; letting the internal bisector YX cut OE in X and the external one YZ cout OW in Z. Then the perpendiculars to WE through these points hit the circle in the four other vertices A,B,C,D as shown.
John Conway

