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International Contests
Baltic Way
2016 Baltic Way
18
18
Part of
2016 Baltic Way
Problems
(1)
Find an angle
Source: Baltic Way 2016, Problem 18
11/5/2016
Let
A
B
C
D
ABCD
A
BC
D
be a parallelogram such that
∠
B
A
D
=
6
0
∘
.
\angle BAD = 60^{\circ}.
∠
B
A
D
=
6
0
∘
.
Let
K
K
K
and
L
L
L
be the midpoints of
B
C
BC
BC
and
C
D
,
CD,
C
D
,
respectively. Assuming that
A
B
K
L
ABKL
A
B
K
L
is a cyclic quadrilateral, find
∠
A
B
D
.
\angle ABD.
∠
A
B
D
.
geometry