sin^-1(11/12sin(73))

Assuming it is 73 degrees.

\(\sin^{-1} (\frac{11}{12}*\sin(73^{\circ}))\)

 

Just type this whole thing into the calculator.

\(\sin^{-1} (\frac{11}{12}*\sin(73^{\circ})) \approx 61.236\)