Answer:
3.5 centimeters.
Step-by-step explanation:
If the perimeter is equal to 11.5 centimeters, and we have the lengths of 2 sides, we can add them together and subtract that sum from the perimeter to get the value of the missing side length.
2.5 + 5.5 = 8
11.5 - 8 = 3.5
Therefore, the side length is equal to 3.5.
