Permutations and Combinations Part 1

We need 3 points to create a triangle. With 10 points number of triangle possible ‌10C3
Here 6 points are on the same line so we can't make any triangle with those 6 points.
So subtract ‌6C3.
∴N=‌10C3−‌6C3
=‌

10.9.8

1.2.3

−‌

6.5.4

1.2.3

=120−20
=100