Why is Math.Cos returning the wrong value?

Question

In my code:

Vector2 colCircle = new Vector2();

colCircle = new Vector2((R * Math.Sin(D)), -(R * Math.Cos(D)));

While:

R = 22.627
D = 89.214

When checked on my calculator, the X value is correct, but the Y value should be -0.310 but in program it is -7.134.

Any ideas why?

Answer 1

The trigonometric functions expect radians, not degrees.