There is a 5 by 5 matrix of points on a plane. How many triangles can be formed using points on this matrix?
There is a 5 by 5 matrix of points on a plane. How many triangles can be formed using points on this matrix?
3
$\begingroup$
combinatorics
puzzle
permutations
-
1Count the triples of points which do not give a triangle, and then subtract from the total. – 2010-11-01