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0|0|0|||||Pentagon Approximation Credited to Durer|Dave Blake|1|06:32:15|06/24/2008|The construction of an approximate pentagon from a vesica %28as in page http%3A%2F%2Fwww.cut-the-knot.org%2Fpythagoras%2FDurerPentagon.shtml%29 is often credited to Albrecht D%FCrer%2C but in fact no one knows for certain where it originally comes from.%0D%0A%0D%0AI thought that you might be interested in some earlier references to this construction that I came across in an addendum to %22The Geometer%27s Angle No. 4%3A From Pentagon to Heptagon%3AA Discovery on the Generation of the Regular Heptagon from the Equilateral Triangle and Pentagon%22 by Mark A Reynolds alias %22Marcus the Marinite%22. The original article was published in NEXUS NETWORK JOURNAL VOL. 3%2C NO 2%2C 2001%2C and having found the addendum online some time ago it no longer seems to be available so I can%27t give a link.%0D%0A%0D%0AMark Reynold%27s points out that the contsruction is found in the book %22Geometrica Deutsch%22 probably published by Roriczer ca. 1472-1484. So it exists 50 years before the 1525 publication of %22Underweysung der Messing mit Zirkel und Richtscheit%22 %28Treatise on Mensuration with Compass and Ruler%29 by D%FCrer%2C in which this drawing can be found. It also subsequnetly appears in %22La pratica della perspettiva%22 by Daniele Barbaro published 1569.%0D%0A%0D%0AHis construction of a heptagon is also worth exploring.
1|1|0|||||RE%3A Pentagon Approximation Credited to Durer|alexb||16:42:34|06/24/2008|Dave%2C %0D%0A%0D%0Amany thanks for the note. I have amended the page.%0D%0A%0D%0AAlex
2|2|1|||||RE%3A Pentagon Approximation Credited to Durer|C. Reineke|1|08:48:16|06/21/2010|Alex%2C%0D%0A%0D%0Ahere is D%FCrer%92s book%2C it%92s figure 16  %28Note the correct spelling of the title%2C please%29%3A%0D%0A%0D%0Ahttp%3A%2F%2Fde.wikisource.org%2Fwiki%2FUnderweysung_der_Messung%2C_mit_dem_Zirckel_und_Richtscheyt%2C_in_Linien%2C_Ebenen_unnd_gantzen_corporen%2FZweites_Buch.%0D%0A%0D%0AIf you want to have a look at the rest%2C just click on %93erstes Buch%94 %28first book%29%2C %93drittes Buch%94 %28third book%29 or %93viertes Buch%94 %28fourth book%29. You will find some very nice constructions%85%0D%0A%0D%0AHere is Roriczer%92s book and his construction%3A%0D%0A%0D%0Ahttp%3A%2F%2Fwww.hs-augsburg.de%2F%7Eharsch%2Fgermanica%2FChronologie%2F15Jh%2FRoriczer%2Fror_g02r.html%0D%0A%0D%0ADave is right%21%0D%0A%0D%0A%0D%0AKind regards%0D%0A%0D%0AChris%0D%0A
3|3|2|||||RE%3A Pentagon Approximation Credited to Durer|alexb||09:21:52|06/21/2010|Thank you%2C Chris.%0D%0A%0D%0AI have upgraded the page with the original diagram. And I shall keep these links in mind. Very interesting.