Consider the point (-6, -8) on the circle x^2 + y^2 = 100. a) Determine the primary trigonometric ratios for the principal angle. b) Determine the principal angle to the nearest degree.
a) r = 10 x = -6 y = -8
sin A = -8/10 = -4/5
cos A = -6/10 = -3/5
tan A = -8/-6 = 4/3
cot A = 3/4
sec A = 5/-3
csc A = -5/4
b) arcsin (-4/5) = -53.1°
However, this angle lies in Quad 3 because both x and y are negative
So....the angle is 180 + 53.1 = 233.1°
+180 
