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

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 rb Posts: 1 Registered: 2/18/08
Re: Geometry Problem
Posted: Feb 18, 2008 5:46 PM
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Kaba ha usato la sua tastiera per scrivere :
>> 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.

I'm not sure if an equation system is needed. I guess drawing a few
parallels and looking for properties like angle bisector theorem,
Thales' theorem, etc... should do the trick by showing two similar
triangles.

Anyway, I don't have any hint, this is only my approach so it could
also be wrong ;)

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

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