In a parallelogram, the diagonals bisect each other. This means that the point where the diagonals intersect divides each diagonal into two equal parts.
Given that \( SU \) is 11 inches, and since \( R \) is the midpoint of diagonal \( SU \), we can find the length of \( SR \) by dividing the length of \( SU \) by 2.
\[ SR = \frac{SU}{2} = \frac{11 \text{ inches}}{2} = 5.5 \text{ inches} \]
Thus, the length of \( SR \) is \( 5.5 \) inches.