26.6
RS is similar to NM, and TP is similar to OL.
If they're similar they have to be proportional. So:
[tex]\begin{gathered} \frac{NM}{RS}=\text{ }\frac{OL}{TP}\text{ } \\ \frac{7}{RS}=\frac{5}{19} \\ RS\text{ = }\frac{19\left(7\right)}{5} \\ RS=\text{ 133/5} \\ RS=26.6 \end{gathered}[/tex]
