Answer
(a) $ 43.97^\circ$
(b) $ 22.72^\circ$
(c) $ 125.47^\circ$
Work Step by Step
Use a scientific calculator, set the unit to $DEG$, we can approximate:
(a) $sin^{-1}(0.69431882)\approx43.97^\circ$
(b) $sec^{-1}(1.0840880)=cos^{-1}(\frac{1}{1.0840880})\approx22.72^\circ$
(c) $cot^{-1}(-0.7125586)=180^\circ+tan^{-1}(\frac{1}{-0.7125586})\approx125.47^\circ$
