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Poland - Second Round
1963 Poland - Second Round
4
4
Part of
1963 Poland - Second Round
Problems
(1)
4 projections are collinear
Source: Polish MO Second Round 1963 p4
8/31/2024
In the triangle
A
B
C
ABC
A
BC
, the bisectors of the internal and external angles are drawn at the vertices
A
A
A
and
B
B
B
. Prove that the orthogonal projections of the point
C
C
C
on these bisectors lie on one straight line.
geometry
collinear