You need to remember the Triangl inequality Theorem. This states that
Let be "a", "b" and "c" the sides of a triangle. According to the Theorem mentioned above:

In this case, knowing two sides of the triangle, you can set up that:
![\begin{gathered} a=28\operatorname{cm} \\ b=82\operatorname{cm} \end{gathered}]()
Let be "c" the third side of this triangle. You know that:
![\begin{gathered} 28\operatorname{cm}+82\operatorname{cm}>c \\ 110\operatorname{cm}>c \end{gathered}]()
Therefore, as you can notice, the third side can be less than 110 centimeters.
Based on the explained before, you can conclude that the third side can be:
![\begin{gathered} c<110\operatorname{cm} \\ \end{gathered}]()
And it can be:
![\begin{gathered} c>82\operatorname{cm}-28\operatorname{cm} \\ c>54\operatorname{cm} \end{gathered}]()
The answers are:
- The longest the third side can be is:
![109\operatorname{cm}]()
- The shortest the third side can be is:
![55\operatorname{cm}]()