Question

What is the angle, in radians, of arcsin(1/2)

Answer 1

$\frac{\pi}{6}$

When you are asked what is the sin of π/6, or 30 degrees, you would look at the special triangle (30-60-90) to see that sin, or opposite over hypotenuse, of π/6 is 1/2.  Arcsin, or csc, will present you with the ratio, 1/2, and ask for the angle.  It's essentially working the question backwards.