η=1sinθ\eta = \frac{1}{\sin\theta}η=sinθ1
1.5=1sinθ1.5 = \frac{1}{\sin\theta}1.5=sinθ1
sinθ=11.5=0.667\sin\theta = \frac{1}{1.5} = 0.667sinθ=1.51=0.667
θ=sin−1(0.667)=41.835∘\theta = \sin^{-1}(0.667) = 41.835^{\circ}θ=sin−1(0.667)=41.835∘
≈41.8∘\approx 41.8^{\circ}≈41.8∘
