In order to calculate the unknown reaction force, we need to know that the sum of forces pointing down is equal the sum of the forces pointing up, so all forces will be in equilibrium.
So we have:
[tex]\begin{gathered} 17800+150000+13200=121000+x \\ 181000=121000+x \\ x=181000-121000 \\ x=60000 \end{gathered}[/tex]