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 Isosceles trapezium
Сообщение24.09.2011, 11:46 
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It is given trapezium ABCD with base AB and intersection point of the diagonals E. M is the middle of AE, N is the middle of CD. P is the foot of the perpendicular from E to AD. If MP is perpendicular to NP find the angles of the trapezium.

Is it correct problem as is?
What if?
1) trapezium is isocsceles.
2) BC=CD=DA

 
 
 
 Re: Isosceles trapezium
Сообщение29.09.2011, 15:19 
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ins- в сообщении #485854 писал(а):
Is it correct problem ...?

No.

 
 
 
 Re: Isosceles trapezium
Сообщение29.09.2011, 22:44 
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I had a reason to ask this question.

I tried to "discover" a beautiful problem about midline in triangle and I observed the following:

It is given a regular pentagon ABCDE. F is the intersection point of the diagonals AD and BE. M and N are the middles of the segments AE and BF. Prove that if P is the foot of the perpendicular from F to AB then MP and NP are perpendicular.

It is very easy problem and can be solved with inscribed angles or using midline. Based on this information I tried to "discover" a problem about finding angles in trapezium that have not standard values.

 
 
 
 Re: Isosceles trapezium
Сообщение30.09.2011, 00:19 
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Take a square insted of trapezium. Satisfy your condition, you can bild any more trapezium either.
(Извиняюсь за мой корявый английский :-) )

 
 
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