Let me venture a guess.... Since you've stated that $(0.38, 0.371)$ is a point on your graph of $y = \sin x$, your calculating device must be in radians mode. Indeed, $\sin(0.38) = 0.371$. Now the graph you've included as a link in the comments section shows $y = \sin x$ if the angle $x$ is measured in degrees. So when you say you want to convert $(0.38, 0.371)$ to $(degree, 0.371)$, then all you need is the conversion factor, $ \mathrm{Degrees} = \mathrm{Radians} \times \frac{180^{\circ}}{\pi} $
In particular, $0.38 \times \frac{180^{\circ}}{\pi} \approx 21.77^{\circ}$.
(Note, what is confusing about your post is your mention of $\sin^{-1} 1$ and $\sin^{-1} 2$, which have nothing to do with the rest of the stated question. Moreover, your graph shows the intersections of $y = \sin x$ with the line $y = 0.75$, so did you really mean to ask about the $x$-value(s) when $y = 0.75$?)
Hope this helps!