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Problems
Contests
National and Regional Contests
Switzerland Contests
Switzerland Team Selection Test
2002 Switzerland Team Selection Test
2
2
Part of
2002 Switzerland Team Selection Test
Problems
(1)
<AOB + < COD = \pi inside parallelogram ABCD => < CBO =< CDO
Source: Switzerland - Swiss TST 2002 p2
2/18/2020
A point
O
O
O
inside a parallelogram
A
B
C
D
ABCD
A
BC
D
satisfies
∠
A
O
B
+
∠
C
O
D
=
π
\angle AOB + \angle COD = \pi
∠
A
OB
+
∠
CO
D
=
π
. Prove that
∠
C
B
O
=
∠
C
D
O
\angle CBO = \angle CDO
∠
CBO
=
∠
C
D
O
.
geometry
parallelogram
equal angles