How many triangles are there in a rectangle with one diagonal?
How many diagonals are there in a triangle?
If Arjun has a quadrilateral ABCD, how many triangles are there in the quadrilateral such that one of the diagonal forms one of the sides of the triangle?
If I have a quadrilateral PQRS, how many triangles are there in the quadrilateral in which I must have one of the diagonals as a side.