Answer
If $\theta_{1} = \theta_{2}$,
\[n_{1} = n_{2}\]
Work Step by Step
From (a), $n_{1}\sin\theta_{1} = n_{2}\sin\theta_{2}$
If $\theta_{1} = \theta_{2}$, we have that
\[n_{1} = n_{2}\]
which indicates that the indices of refraction for the two mediums are the same.
