Given six non-parallel line segments of lengths 2, 3, 4, 5, 6, 7 units, the number of triangles that can be formed by these lines is _____.
- 7
Total No. of triangles = 6C3
To form a triangle sum of two sides of triangle should be greater than third side.
2+ 3 is NOT greater than 5, 6 and 7 units
2 + 4 is NOT greater than 6 and 7 units
2 + 5 is NOT greater than 7 units
4 + 3 is NOT greater than 7 units
We see that there are seven-cases for which sum of two sides of triangle is not greater than third side.
So, No. of triangles =6C3 - 7