The length of the missing side is 19.4. We can use the Pythagorean theorem to solve for the length of the missing side.
Since all the sides of a triangle are positive, the length of the missing side must be equal to the difference of the two other sides.
Using the Pythagorean Theorem, we can calculate the length of the missing side as follows:

Therefore, the length of the missing side is 53.2 units.