A helper to convert degrees (360 in a circle) to Rad (\(2\pi\) in a circle, so \(deg x 180/\pi\) to get radians.
note: R's trig functions, e.g. sin()
use Radians for input!
180 Degrees is equal to \(\pi\) radians. 1 Rad = \(180/\pi\) degrees (\(\approx 57.296^{\circ}\))