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# Nine points

### #1 witzar

witzar

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Posted 25 June 2013 - 09:01 AM

Nine points are given on the plane, no three of which are collinear.
Each pair of points is connected with segment, that is painted either white or black.
Prove that there exists either quadrilateral with white sides and diagonals or triangle with black sides.

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### #2 bonanova

bonanova

bonanova

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Posted 25 June 2013 - 10:07 PM

Nine points are given on the plane, no three of which are collinear.
Each pair of points is connected with segment, that is painted either white or black.
Prove that there exists either quadrilateral with white sides and diagonals or triangle with black sides.

Spoiler for sounds like

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The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

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