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2
Quadraliteral with strange angles
Quadraliteral with strange angles
Source:
January 6, 2008
geometry
circumcircle
geometry unsolved
Problem Statement
In a convex quadrilateral
A
B
C
D
ABCD
A
BC
D
, both
∠
A
D
B
=
2
∠
A
C
B
\angle ADB=2\angle ACB
∠
A
D
B
=
2∠
A
CB
and
∠
B
D
C
=
2
∠
B
A
C
\angle BDC=2\angle BAC
∠
B
D
C
=
2∠
B
A
C
. Prove that
A
D
=
C
D
AD=CD
A
D
=
C
D
.
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