There are buttons on all scientific calculators for inverse trig functions.
Usually denoted as "arcsin, arccos" or with a little -1 inverse sign like this:
[tex] sin^{-1} (0.2588) = 14.99[/tex]
You put in the measurement and it gives back the angle. I
angle x = 15°
complimentary angles add up to 90° so the angle that's complimentary is 90-15 = 75°
