There are 7 non-collinear points. How many triangles can be drawn by joining these points?

A triangle is formed by joining any three non-collinear points in pairs.
There are 7 non-collinear points.
The number of triangles formed,
$$\eqalign{ & { = ^7}{{\text{C}}_3} \cr & = \frac{{7 \times \left( {7 - 1} \right) \times \left( {7 - 2} \right)}}{{3!}} \cr & = \frac{{7 \times 6 \times 5}}{{3 \times 2 \times 1}} \cr & = 7 \times 5 \cr & = 35 \cr} $$