Find the number of triangles which can be formed by joining the angular points of a polygon of 8 sides as vertices.

Answer: Option A

A triangle needs 3 points.
And polygon of 8 sides has 8 angular points.
Hence, number of triangle formed,
$$\begin{array}{rl}& {=}^8{\text{C}}_3\\ & =\frac{8\times 7\times 6}{1\times 2\times 3}\\ & =56\end{array}$$