
Re: How to prove that angle in a Circle is 2 Pi Rads ?
Posted:
Jun 4, 2009 8:43 PM


In article <ken.pledger1BCED6.08381105062009@mara10084.onlink.net> Ken Pledger <ken.pledger@mcs.vuw.ac.nz> writes: > In article > <659af571e4444af9adfda0efd8be622b@f10g2000vbf.googlegroups.com>, > calvin <crice5@windstream.net> wrote: > > I've often wondered how the ancients were able to > > find the value of pi so precisely as to know that > > it is not rational.... > > AFAIK they didn't. The irrationals in Euclid Book X are all > algebraic numbers built up from square roots.
They did not know that pi is irrational. The first proof dates from the 18th century. A short proof (requiring not much more than calculus, but more than the Greek knew about) was found in 1947.  dik t. winter, cwi, science park 123, 1098 xg amsterdam, nederland, +31205924131 home: bovenover 215, 1025 jn amsterdam, nederland; http://www.cwi.nl/~dik/

