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

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 Nat Silver Posts: 2,082 Registered: 12/6/04
Re: Geometry Problem
Posted: Feb 19, 2008 1:41 AM

Carl Barron wrote:
> Kaba wrote:

>>> Hi all,
>>> I need help with this problem:
>>> http://img180.imageshack.us/img180/8286/20080218181526nq7.gif
>>> The angle to find is ECD.
>>> The matter is solving it without trigonometric functions.
>>> With trigonometry or by drawing it you can see that the angle to find
>>> is 20° (sessagesimal) but I can't find it using a simple solution
>>> (properties of triangles, the parallel postulate and so on).
>>> Can you solve it?

>> Interesting problem, couldn't solve it either. I get 4 unknowns but only
>> 3 linearly independent equations.

> consider triangles BDC and ECD and their angles as well as
> intersecting and straight lines. Pretty easy no real equations
> just bookkeeping....

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