Ray Optics

For a thin prism, $\delta_1$ is the angle of deviation produced, when prism is placed in air. When the prism is immersed in water, the angle of deviation produced is $\delta_2$. Given ${ }_{\mathrm{a}} \mu_{\mathrm{g}}=\frac{3}{2}$ and ${ }_{\mathrm{a}} \mu_{\mathrm{w}}=\frac{4}{3}$. The ratio $\delta_2: \delta_1$ is