Degrees

360 degrees in a circle

Radians

2 PI = 360 degrees = 6.283185307179586 radians.
PI = 180 degrees = 3.141592653589793 radians.
and PI / 2 = 90 degrees = 1.5707963267948966 radians.
0 degrees = 0 radians.

Flash

Flash’s rotation property uses degrees
Math trig functions use radians

In Flash use Math.PI for "pi" value. Math.PI is a mathematical constant for the ratio of the circumference of a circle to its diameter, expressed as pi, with a value of 3.141592653589793.

Converting from degrees to radians

radians = degrees * Math.PI / 180

Converting from radians to degrees

degrees = radians * 180 / Math.PI

ActionScript 3.0 examples

degrees to radians

trace("Math.PI = ", Math.PI);
trace("360 degrees = ", 360 * Math.PI / 180, " radians.");
trace("180 degrees = ", 180 * Math.PI / 180, " radians.");
trace("90 degrees = ", 90 * Math.PI / 180, " radians.");
trace("0 degrees = ", 0 * Math.PI / 180, " radians.");

OUTPUT

Math.PI =  3.141592653589793
360 degrees =  6.283185307179586  radians.
180 degrees =  3.141592653589793  radians.
90 degrees =  1.5707963267948966  radians.
0 degrees =  0  radians.
 

var angle:Number = 45;
var radians:Number = angle * Math.PI/180;
trace (Math.sin(radians));

var input:Number = .707;
trace(Math.asin(input) * 180 / Math.PI);

Definitions
Sine
sin(angle) = y / c (c = hypotenuse)
Cosine
cos(angle) = x / c (c = hypotenuse)