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China National Olympiad
1991 China National Olympiad
1
1
Part of
1991 China National Olympiad
Problems
(1)
China Mathematical Olympiad 1991 problem1
Source: China Mathematical Olympiad 1991 problem1
10/8/2013
We are given a convex quadrilateral
A
B
C
D
ABCD
A
BC
D
in the plane. (i) If there exists a point
P
P
P
in the plane such that the areas of
△
A
B
P
,
△
B
C
P
,
△
C
D
P
,
△
D
A
P
\triangle ABP, \triangle BCP, \triangle CDP, \triangle DAP
△
A
BP
,
△
BCP
,
△
C
D
P
,
△
D
A
P
are equal, what condition must be satisfied by the quadrilateral
A
B
C
D
ABCD
A
BC
D
? (ii) Find (with proof) the maximum possible number of such point
P
P
P
which satisfies the condition in (i).
geometry