It's not possible to build a triangle with side lengths of 7 6 and 9?

Answer 1

Yes, it's possible. The requirement is that each side must be shorter than the sum of the other two sides.

In this case, 7 is shorter than 6 + 9, 6 is shorter than 7 + 9, and 9 is shorter than 7 + 6. Consequently, you can build a triangle with sides of length 7, 6, and 9.