- A whole circle is
`360`

degrees or`Math.PI * 2`

radians. - Half of those values follows to be
`180`

degrees or`Math.PI`

radians. - A quarter is then
`90`

degrees or`Math.PI / 2`

radians.

To get a segment as a percentage of a whole circle in radians:

```
function getSegment(percent:Number):Number {
return Math.PI * 2 * percent;
}
var tenth:Number = getSegment(0.1); // One tenth of a circle in radians.
```