MathDB
Problems
Contests
International Contests
Junior Balkan MO
2006 Junior Balkan MO
2
2
Part of
2006 Junior Balkan MO
Problems
(1)
Compute angle
Source: JBMO 2006
6/29/2006
The triangle
A
B
C
ABC
A
BC
is isosceles with
A
B
=
A
C
AB=AC
A
B
=
A
C
, and
∠
B
A
C
<
6
0
∘
\angle{BAC}<60^{\circ}
∠
B
A
C
<
6
0
∘
. The points
D
D
D
and
E
E
E
are chosen on the side
A
C
AC
A
C
such that,
E
B
=
E
D
EB=ED
EB
=
E
D
, and
∠
A
B
D
≡
∠
C
B
E
\angle{ABD}\equiv\angle{CBE}
∠
A
B
D
≡
∠
CBE
. Denote by
O
O
O
the intersection point between the internal bisectors of the angles
∠
B
D
C
\angle{BDC}
∠
B
D
C
and
∠
A
C
B
\angle{ACB}
∠
A
CB
. Compute
∠
C
O
D
\angle{COD}
∠
CO
D
.
geometry
incenter