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.

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