To find the missing side of the right triangle, we can use the Pythagorean theorem, which states:
\[ a^2 + b^2 = c^2 \]
In this case, we need to determine which two sides we have. From your question, it appears we have two side lengths: 38 and 9.
Assuming 38 is the hypotenuse \(c\) (the longest side) and 9 is one of the legs \(a\), we can find the other leg \(b\) using the formula:
\[ 9^2 + b^2 = 38^2 \]
Calculating the squares gives:
\[ 81 + b^2 = 1444 \]
Now, we can isolate \(b^2\):
\[ b^2 = 1444 - 81 \]
\[ b^2 = 1363 \]
Now, take the square root to find \(b\):
\[ b = \sqrt{1363} \approx 36.9 \]
Rounding to the nearest tenth, the length of the missing side is:
\[ \boxed{36.9} \]