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1966 IMO Shortlist
41
41
Part of
1966 IMO Shortlist
Problems
(1)
Socialists Republic Of Czechoslovakia 7
Source: IMO LongList 1959-1966 Problem 41
9/2/2004
Given a regular
n
n
n
-gon
A
1
A
2
.
.
.
A
n
A_{1}A_{2}...A_{n}
A
1
A
2
...
A
n
(with
n
≥
3
n\geq 3
n
≥
3
) in a plane. How many triangles of the kind
A
i
A
j
A
k
A_{i}A_{j}A_{k}
A
i
A
j
A
k
are obtuse ?
geometry
polygon
counting
Obtuse triangle
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