[Woodcarver] Geometry question for the group

[Classic Carving Patterns]

It's been a very long time since I have had to do any geometry equations
... But as I remember a prime number is defined as being evenly
divisible only by 1 and by itself; 13 divided by 1 = 13 and 13 divided
by 13 = 1. So what I would do is first create a circle that has a 13"
circumference.  Therefore you have a point every one inch along the
outer circumference line and you have a center point to create the
radius lines.  Those lines will be true then for any sized circle that
you need, you only need to extend them to the new outer edge of the
larger circle.

Susan

Carving Patterns Online
Designs Online Since 1997!
Classic Carving Patterns By L.S.Irish
http://www.CarvingPatterns.com
http://www.WoodCarvingPatterns.com



-----Original Message-----
From: woodcarver-bounces at six.pairlist.net
[mailto:woodcarver-bounces at six.pairlist.net] On Behalf Of Victor
Hamburger
Sent: Thursday, September 30, 2004 8:53 AM
To: [Woodcarver]
Subject: Re: [Woodcarver] Geometry question for the group


To make a DONATION to the Mailing List using PayPal OR regular mail,
click this link: http://wwwoodcarver.com/WWWList/WWWList.html

Tom Clarke wrote:
> 
> Are just some of what's out there. Using the formula's given a side
> length or taking an exterior circle one could then draw the polygon
for any sided.
> Problem with one with 13 sides is the angle isn't a whole number.
Probably give you
> fits.

Tom, and Ivan,

Thanks for the comments, I had found the DrMath site but didn't try the
math. 
13 is a prime number, indivisible except by 1, causing some of the
problem. 
What I want to understand is how, using only a compass and straightedge,
do you 
lay out the 13 point star.  I have various solutions for 4,5,6,8 and 12
point 
stars.  I can bisect any of those sides to create a star with twice
those 
points, but 13, being prime, has got to be done by itself.

The builders 800+ yrs ago knew how to do it with a compass and
straightedge, and 
I would like to duplicate that.  As I said, I can lay it out with a CAd
program 
no problem, I just like the challenge of doing it with the simple tools
of the 
master craftsman of earlier times.  The pyramids and Greek Temples and
Roman 
empire were built with these tools, I am curious to try a more complex
figure 
for myself.

Thanks,  Vic H


_______________________________________________
Woodcarver mailing list
Woodcarver at six.pairlist.net
http://six.pairlist.net/mailman/listinfo/woodcarver