Answer:
Without additional context or information, it's difficult to determine the missing side length with certainty. However, we can use some logical reasoning to make an educated guess.
One possible way to approach this problem is to look for relationships between the known side lengths and the missing side length. For example, we can look at the lengths of the sides that are adjacent to the missing side and see if there are any patterns or ratios that might help us determine the length of the missing side.
In this case, we can see that the missing side is adjacent to sides with lengths of 8 and 9, which have a difference of 1. If we assume that the sides of the figure form a regular pattern or sequence, then we might guess that the missing side has a length that is 1 greater than 9, which would give us a length of 10 for the missing side.
However, this is just a guess based on the limited information provided, and there could be other possible solutions depending on the specific properties or context of the figure.