Difference between revisions of "2020 OIM Problems/Problem 1"

(Created page with "== Problem == Let ABC be an acute triangle such that AB < AC. The midpoints of the Sides AB and AC are M and N, respectively. Let P and Q be points on the line MN such that \C...")
 
 
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== Problem ==
 
== Problem ==
Let ABC be an acute triangle such that AB < AC. The midpoints of the
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Let <math>ABC</math> be an acute triangle such that <math>AB < AC</math>. The midpoints of sides <math>AB</math> and <math>AC</math> are <math>M</math> and <math>N</math>, respectively. Let <math>P</math> and <math>Q</math> be points on the line <math>MN</math> such that <math>\angle CBP = \angle ACB</math> and <math>\angle QCB = \angle CBA</math>. The circumcircle of triangle <math>ABP</math> intersects the line <math>AC</math> in <math>D</math> (<math>D \ne A</math>) and the circumcircle of the triangle <math>AQC</math> intersects the line <math>AB</math> in <math>E</math> (<math>E \ne A</math>). Show that the lines <math>BC</math>, <math>DP</math> and <math>EQ</math> are concurrent.
Sides AB and AC are M and N, respectively. Let P and Q be points on the line MN such that
 
\CBP = \ACB and \QCB = \CBA. The circumcircle of triangle ABP intersects
 
to the line AC in D (D 6= A) and the circumcircle of the triangle AQC intersects the
 
line AB in E (E 6= A). Show that the lines BC, DP and EQ are concurrent.
 
  
 
~translated into English by Tomas Diaz. ~orders@tomasdiaz.com
 
~translated into English by Tomas Diaz. ~orders@tomasdiaz.com

Latest revision as of 12:43, 14 December 2023

Problem

Let $ABC$ be an acute triangle such that $AB < AC$. The midpoints of sides $AB$ and $AC$ are $M$ and $N$, respectively. Let $P$ and $Q$ be points on the line $MN$ such that $\angle CBP = \angle ACB$ and $\angle QCB = \angle CBA$. The circumcircle of triangle $ABP$ intersects the line $AC$ in $D$ ($D \ne A$) and the circumcircle of the triangle $AQC$ intersects the line $AB$ in $E$ ($E \ne A$). Show that the lines $BC$, $DP$ and $EQ$ are concurrent.

~translated into English by Tomas Diaz. ~orders@tomasdiaz.com

Solution

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See also

OIM Problems and Solutions