Question

6 points are placed on the line a , 4 points are placed on the line b . How many triangles is it possible to form such that their vertices will be the given points, if a ∥ b ?

Answer 1

7

Explanation:

Given line a with 6 points on it, and line b with 4 points on it. Line a is parallel to line b, such that the two lines do not meet at any point even when extended.

Join the first point on line a to that on b, then back to the second point on a, return back to the second point on b, and continue till the line stops at the 5th point on line a. This forms triangles with vertices at the given points on the lines. The possible number of triangles that can be formed is 7.