Without further information, you can't deduce the length of one side of a triangle knowing the other two.
You can only use the inequalities that tell you that the sum of two sides is greater than the remaining one to get
![x+16 > 19 \implies x > 3](https://img.qammunity.org/2020/formulas/mathematics/college/e9s9go7puxjmrxrm32ntge66ffnw2se0o5.png)
which is true for all positive x values
![16+19 > x \implies x < 35](https://img.qammunity.org/2020/formulas/mathematics/college/so82mjgd68wr420p46qzwec77pi1453zji.png)
So, knowing only the length of two of the sides, we can only say that the third side is between 3 and 35 inches long.