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Sharygin CR 2019 P2

Source:

March 6, 2019

geometry

Problem Statement

The circle

\omega_1

passes through the center

O

of the circle

\omega_2

and meets it at points

A

and

B

. The circle

\omega_3

centered at

A

with radius

AB

meets

\omega_1

and

\omega_2

at points

C

and

D

(distinct from

B

). Prove that

C, O, D

are collinear.

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