1. Determine the principal angle(s) for x in each of the following situations (rounded to the nearest tenth of a degree):
a) sin x = -0.3121
b) cos x = 0.4107
c) tan x = -0.2151
Answers (approximate, in degrees): a) 198.2, 341.8 b) 65.8, 294.2 c) 167.9, 347.9