arcsin((√3)/2)

You can plug this into a calculator: $$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}^{\!\!\mathtt{-1}}{\left({\frac{{\sqrt{{\mathtt{3}}}}}{{\mathtt{2}}}}\right)} = {\mathtt{60^{\circ}}}$$

Or, you can use the unit circle (a circle with a radius of 1 which is very useful for finding exact values of angles with 30, 45, and 60 degree reference angles).

This page explains it more if you're interested: http://www.mathsisfun.com/geometry/unit-circle.html

We're looking for an angle where the sine = (√3)/2

This happens at 60 degrees and at 120 degrees

A more general solution (in degrees) would be..... 60 + n360  and 120 +n360  where n is an integer

In radians, the general solution would be ... pi/3 + n(2pi)   and 2pi/3 + n(2pi)  where n is an integer