Sin x = 3/4

Just use the calculator here to find x.  x = sin^-1(3/4)   This may also be written as asin(3/4).

You should find that x = 48.59° (In the first quadrant.  It could also be 180° - 48.59° = 131.41° in the second quadrant).

$${\mathtt{x}} = \underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}^{\!\!\mathtt{-1}}{\left({\frac{{\mathtt{3}}}{{\mathtt{4}}}}\right)} \Rightarrow {\mathtt{x}} = {\mathtt{48.590\: \!377\: \!890\: \!729^{\circ}}}$$