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Flanders Math Olympiad
2010 Flanders Math Olympiad
3
3
Part of
2010 Flanders Math Olympiad
Problems
(1)
AB//CD when <B= 2<A , angle bisector of B intersects perp.bisector of AC at D
Source: 2010 VWO Flanders MO p3
8/7/2020
In a triangle
A
B
C
ABC
A
BC
,
∠
B
=
2
∠
A
≠
9
0
o
\angle B= 2\angle A \ne 90^o
∠
B
=
2∠
A
=
9
0
o
. The inner bisector of
B
B
B
intersects the perpendicular bisector of
[
A
C
]
[AC]
[
A
C
]
at a point
D
D
D
. Prove that
A
B
∥
C
D
AB \parallel CD
A
B
∥
C
D
.
geometry
angle bisector
parallel
perpendicular
angles