MathDB
Problems
Contests
National and Regional Contests
Russia Contests
Moscow Mathematical Olympiad
1955 Moscow Mathematical Olympiad
300
MMO 300 Moscow MO 1955 AC - DA > 1, BC - BD > 1, EC - ED > 1
MMO 300 Moscow MO 1955 AC - DA > 1, BC - BD > 1, EC - ED > 1
Source:
August 17, 2019
geometry
geometric inequality
Problem Statement
Inside
△
A
B
C
\vartriangle ABC
△
A
BC
, there is fixed a point
D
D
D
such that
A
C
−
D
A
>
1
AC - DA > 1
A
C
−
D
A
>
1
and
B
C
−
B
D
>
1
BC - BD > 1
BC
−
B
D
>
1
. Prove that
E
C
−
E
D
>
1
EC - ED > 1
EC
−
E
D
>
1
for any point
E
E
E
on segment
A
B
AB
A
B
.
Back to Problems
View on AoPS