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Iran MO (2nd Round)
2022 Iran MO (2nd round)
1
1
Part of
2022 Iran MO (2nd round)
Problems
(1)
D'B, E'C and l are congruence.
Source: 2022 Iran second round mathematical Olympiad P1
5/22/2022
Let
E
E
E
and
F
F
F
on
A
C
AC
A
C
and
A
B
AB
A
B
respectively in
△
A
B
C
\triangle ABC
△
A
BC
such that
D
E
∣
∣
B
C
DE || BC
D
E
∣∣
BC
then draw line
l
l
l
through
A
A
A
such that
l
∣
∣
B
C
l || BC
l
∣∣
BC
let
D
′
D'
D
′
and
E
′
E'
E
′
reflection of
D
D
D
and
E
E
E
to
l
l
l
respectively prove that
D
′
B
,
E
′
C
D'B, E'C
D
′
B
,
E
′
C
and
l
l
l
are congruence.
geometry