MathDB
Problems
Contests
International Contests
Nordic
2016 Nordic
2
2
Part of
2016 Nordic
Problems
(1)
Nordic 2016 P2
Source:
4/4/2017
Let
A
B
C
D
ABCD
A
BC
D
be a cyclic quadrilateral satysfing
A
B
=
A
D
AB=AD
A
B
=
A
D
and
A
B
+
B
C
=
C
D
AB+BC=CD
A
B
+
BC
=
C
D
. Determine
∡
C
D
A
\measuredangle CDA
∡
C
D
A
.
geometry
cyclic quadrilateral