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Czech-Polish-Slovak Match
2005 Czech-Polish-Slovak Match
5
5
Part of
2005 Czech-Polish-Slovak Match
Problems
(1)
Locus of points for which products of areas are equal
Source: Czech-Polish-Slovak 2005 Q5
4/27/2013
Given a convex quadrilateral
A
B
C
D
ABCD
A
BC
D
, find the locus of the points
P
P
P
inside the quadrilateral such that
S
P
A
B
⋅
S
P
C
D
=
S
P
B
C
⋅
S
P
D
A
S_{PAB}\cdot S_{PCD} = S_{PBC}\cdot S_{PDA}
S
P
A
B
⋅
S
PC
D
=
S
PBC
⋅
S
P
D
A
(where
S
X
S_X
S
X
denotes the area of triangle
X
X
X
).
geometry
conics
analytic geometry
trigonometry
geometry unsolved