Pythagorean theorem

[Robert Holmes]

Re today's discussion about proofs of the Pythagorean theorem - here's a
link to a page with ~80 proofs:
http://www.cut-the-knot.org/pythagoras/index.shtml

Proof #4 is the one that Frank & I were so impressed with; #1 is the one
that Nick (along with anyone who graduated St Johns) failed to reproduce; #5
is the one due to Pres. Garfield (an intelligent president! those were the
days...). And you can get an "extra-geometric" proof that relies on Newton's
2nd law at http://www.cut-the-knot.org/pythagoras/mech.shtml

Robert
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[Roger Frye-3]

Bogomoly's site doesn't mention it, but proof #69 can be thought of as  
an infinite double tiling of the plane.
Furthermore, an infinite number of new proofs can be generated by  
sliding the square an increment in any direction and adding up the  
areas.
So the number of proofs is not just 78.
-Roger

On Jul 4, 2008, at 12:52 PM, Robert Holmes wrote:

> Re today's discussion about proofs of the Pythagorean theorem -  
> here's a link to a page with ~80 proofs: http://www.cut-the-knot.org/pythagoras/index.shtml
>
> Proof #4 is the one that Frank & I were so impressed with; #1 is the  
> one that Nick (along with anyone who graduated St Johns) failed to  
> reproduce; #5 is the one due to Pres. Garfield (an intelligent  
> president! those were the days...). And you can get an "extra-
> geometric" proof that relies on Newton's 2nd law at http://www.cut-the-knot.org/pythagoras/mech.shtml
>
> Robert

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