x=sin^-1(3.9/4.29)
enter this into the calc as
asin(3.9/4.29)
$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}^{\!\!\mathtt{-1}}{\left({\frac{{\mathtt{3.9}}}{{\mathtt{4.29}}}}\right)} = {\mathtt{65.380\: \!022\: \!671\: \!343^{\circ}}}$$