arcsin (-0.31) ≈ -18° = x
990/360 = 2.75 = 2 + 3/4 rotations
We will have two angles in each rotation where sin x = -0.31
360 - 18 = 342°
360 (3/4) = 270°
So....in the last rotation, we only have one angle value where sin x = -0.31
So.... 2(2) + 1 = 5 values of x
