5 articles trouvés pour ce sujet.
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   | A cyclic quadrilateral | 2014-03-28 | 
  |  | Carly pose la question : Suppose ABCD is a cyclic quadrilateral, i.e A, B, C, and D are the points on a circle,
given in order going around the circle. Show that if we join each of A, B, C, and D to the orthocentre
of the triangle formed by the other three, then the resulting line segments all intersect in a common midpoint.
 Thank you.
 Chris Fisher lui répond.
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   | If a parallelogram is a cyclic quadrilateral then it is a rectangle | 2012-02-01 | 
  |  | Kim pose la question : Show that if a parallelogram is a cyclic quadrilateral then it is a rectangle. 
Hint: Observe that in a parallelogram ABCD we always have Triangle ABC is congruent to Triangle CDA.
 Robert Dawson and Chris Fisher lui répond.
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   | A cyclic quadrilateral | 2011-08-15 | 
  |  | Tim pose la question : Hi! I've been working on this for a while and I'm quite stuck. If anyone can help that would be great.
The sides BC and AD of a quadrilateral ABCD are parallel. A circle meets the side AB at B and E and the side CD at C and F. Prove that the quadrilateral AEFD is cyclic.
 Chris Fisher lui répond.
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   | A cyclic quadrilateral | 2009-01-23 | 
  |  | Murtaza pose la question : Line ATB touches a circle at T and TC is a diameter. AC and BC cut the circle at D and E respectively.Prove that the quadrilateral ADEB is cyclic.
 Robert Dawson and Chris Fisher lui répond.
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   | A cyclic quadrilateral | 2006-11-20 | 
  |  | Namrata pose la question : If two sides of a cyclic quadrilateral are parallel, prove that
 (1) remaining two sides are equal,
 (2) both diagonals are equal.
 Penny Nom lui répond.
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