I have a strip of paper with parallel sides, a pencil and a straight edge. How can I construct a regular pentagram (star) with these? And for that matter, a pentagon? Well ... the pentagon is the proper way to go.

It is now a bit over 4 years since I presented this.

I notice some things of interest here.  The maths fwaff presented was interesting and a little bit of history given to us by John, re Betsy Ross I found an interesting aside.

And SilverKnight, I never did advise, other than my final solution, that folding was to provided my intended outcome.  You asked Brian Smith in the same comment about his exposure to this.  I cannot speak for him, but I believe I found this in a paperback authored by Martin Gardner back in the 1970's.

Posted by brianjn on 2008-02-21 09:06:25