Consider the five points comprising of the vertices of a square and the intersection point of its diagonals. How many triangles can be formed using these points?

- 4
- 6
- 8
- 10

**Answer**

You can form a triangle out of any 3 points which are not collinear. Hence, 3 points out of 5 can be chosen in ^{5}C_{3} = 10 ways.

But of these, the three points lying on the two diagonals will be collinear.

So 10 - 2 = 8 triangles can be formed.

**The correct option is C.**