Difference between revisions of "1969 IMO Problems/Problem 5"

(Created page with "Given n > 4 points in the plane such that no three are collinear. Prove that there are at least ³ n-3 ---- 2 ´ convex quadrilaterals whose vertices are four of the given points.")
 
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Given n > 4 points in the plane such that no three are collinear. Prove that
 
Given n > 4 points in the plane such that no three are collinear. Prove that
 
there are at least
 
there are at least
³
+
(n-3)/2
n-3
 
----
 
  2
 
´
 
 
convex quadrilaterals whose vertices are four of the
 
convex quadrilaterals whose vertices are four of the
 
given points.
 
given points.

Revision as of 12:06, 20 October 2013

Given n > 4 points in the plane such that no three are collinear. Prove that there are at least (n-3)/2 convex quadrilaterals whose vertices are four of the given points.