Difference between revisions of "2006 IMO Problems"

(Problem 1)
(Problem 1)
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==Problem 1==
 
==Problem 1==
Let ABC be a triangle with incentre I. A point P in the interior of the triangle satisfies <PBA + <PCA = <PBC +  <PCB.
+
Let <math>ABC be a triangle with incentre I. A point P in the interior of the triangle satisfies </math><PBA + <math><PCA = </math><PBC +  $<PCB.
 
Show that AP ≥ AI, and that equality holds if and only if P = I.
 
Show that AP ≥ AI, and that equality holds if and only if P = I.
  

Revision as of 22:51, 14 February 2019

Problem 1

Let $ABC be a triangle with incentre I. A point P in the interior of the triangle satisfies$<PBA + $<PCA =$<PBC + $<PCB. Show that AP ≥ AI, and that equality holds if and only if P = I.

Problem 2

Let $P$ be a regular 2006-gon. A diagonal of $P$ is called good if its endpoints divide the boundary of $P$ into two parts, each composed of an odd number of sides of $P$. The sides of $P$ are also called good. Suppose $P$ has been dissected into triangles by 2003 diagonals, no two of which have a common point in the interior of $P$. Find the maximum number of isosceles triangles having two good sides that could appear in such a configuration.

Problem 3

Problem 4

Problem 5

Problem 6

See Also