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Topic: Geometry Problem
Replies: 17   Last Post: Feb 20, 2008 10:04 AM

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 Philippe 92 Posts: 614 Registered: 1/25/05
Re: Geometry Problem
Posted: Feb 20, 2008 7:56 AM

I.M. Soloveichik wrote :
> There is not enough information unless that angle at D which looks like it is
> 90 is supposed to be 90--in that case the angle x is 40 degrees.

A constructive proof that there is enough information to get the
*angles* :

Construct on a given base EB the 4 rays with given angles, they
intersect into C and D.
Starting from a different base EB gives just a simiular figure,
hence with all same angles.

And of course the "9O° looking" angle is ... not 90°, but 110°.

Regards.

--
Philippe C., mail : chephip+news@free.fr
site : http://chephip.free.fr/ (recreational mathematics)

Date Subject Author
2/18/08 rb
2/18/08 mensanator
2/18/08 none@here.com
2/18/08 rb
2/19/08 Philippe 92
2/19/08 rb
2/20/08 Carl Barron
2/20/08 Philippe 92
2/20/08 rb
2/20/08 Philippe 92
2/20/08 rb
2/18/08 Carl Barron
2/19/08 Nat Silver
2/19/08 rb
2/19/08 I.M. Soloveichik
2/19/08 rb
2/19/08 briggs@encompasserve.org
2/20/08 Philippe 92