Answer:
n=2.053
Explanation:
We will use Snell's Law defined as:
[tex]n_{1}*Sin\theta_{1}=n_{2}*Sin\theta_{2}[/tex]
Where n values are indexes of refraction and [tex]\theta[/tex] values are the angles in each medium. For vacuum, the index of refraction in n=1. With this we have enough information to state:
[tex]1*Sin(39.9)=n_{2}*Sin(18.2)[/tex]
Solving for [tex]n_{2}[/tex] yields:
[tex]n_{2}=\frac{Sin(39.9)}{Sin(18.2)}=2.053[/tex]
Remember to use degrees for trigonometric functions instead of radians!