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Tournament Of Towns
1995 Tournament Of Towns
(454) 3
(454) 3
Part of
1995 Tournament Of Towns
Problems
(1)
CO _|_ DE wanted, 2 circles related
Source: TOT 454 1995 Spring S O3 - Tournament of Towns
7/9/2024
Triangle
A
B
C
ABC
A
BC
is inscribed in a circle with center
O
O
O
. Let
q
q
q
be the circle passing through
A
A
A
,
O
O
O
and
B
B
B
. The lines
C
A
CA
C
A
and
C
B
CB
CB
intersect
q
q
q
at the points
D
D
D
and
E
E
E
(different from
A
A
A
and
B
B
B
). Prove that the lines
C
O
CO
CO
and
D
E
DE
D
E
are perpendicular to each other.(S Markelov)
perpendicular
geometry