Function sectorP

sectorP(r: number, rad: number): number
Calculates the perimeter of a sector of a circle.
Parameters
- r: number
  The radius
- rad: number
  The spanned radians
Returns number
Example
```
// Returns 15.707963267948967
const perimeter = Chalkboard.geom.sectorP(5, Chalkboard.PI());
```
- Defined in Chalkboard.geom.ts:392