C. A function can only have one y value for an x value
sin(x) = opp/hyp
cos(x) = adj/hyp
tan(x) = opp/adj
sin(x) = 3.9/8.1
sin(x) = 0.481
Inverse sin of 0.481 = 28.8 degrees
Each answer should be between 0 and 90 :)
Triangle= 180 degrees
Angle = 37.5 degrees
Supplement angle = 105 degrees
If you multiply the angle (37.5) by 2 and then add 30, it gives you 105. Then add 37.5 twice to make up the other two angles of the triangle and it gives you 180 total degrees as a triangle should.