If $F_1=\{-50i+140j+63k\}N$ and $F_2=\{-188i+84j+222k\}N,$ determine the magnitude of the resultant moment produced by the forces about point O $.$ Given dimensions $a=1\mathrm{.}3m,b=2\mathrm{.}2$ m and $c=2\mathrm{.}2m($Hint: $M_{OR}=\{M_{x}i+M_{y}j+M_{z}k\}$ N$.$m and $M_{OR}=\sqrt[\phantom{2}]{(M_x{)}^2+(M_y{)}^2+(M_z{)}^2}.$ Using two decimal places.