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incenter-related concurrency

Source: 2001 Moldova MO Grade 8 P7

April 12, 2021

geometryTriangles

Problem Statement

The incircle of a triangle

ABC

is centered at

I

and touches

AC,AB

and

BC

at points

K,L,M

, respectively. The median

BB_1

of

\triangle ABC

intersects

MN

at

D

. Prove that the points

I,D,K

are collinear.

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