Question

Two sides of a triangle have lengths 10 and 18. Which inequalities describe the possible lengths for the third side x?

Answer 1

Let with X is denoted the length of the third side.
For a triangle the following statements must be true:
The sum of the lengths of any two sides of a triangle is greater than the length of the third side.
This means that this inequality can be written: X<10+18 ,X<28