Answer
$\theta _{1}=\sin ^{-1}\left( 0.658\right) \approx 41.14^{0}$
Work Step by Step
$\dfrac {\sin \theta _{1}}{\sin \theta _{2}}=\dfrac {v_{1}}{v_{2}}\Rightarrow \dfrac {\sin \theta _{1}}{\sin 90^{0}}=\dfrac {1}{1.52}\Rightarrow \sin \theta _{1}=\dfrac {\sin 90}{1.52}\approx 0.658$
$\Rightarrow \theta _{1}=\sin ^{-1}\left( 0.658\right) \approx 41.14^{0}$
