Convert degrees to radians

toRadians.js

/**
 * Convert degrees to radians
 * @author Timothy Wood @codearachnid
 * @link http://www.movable-type.co.uk/scripts/latlong.html
 * @example
 
 var latitude = 38.68551;
 var longitude = -96.503906;
 var latitude_radian = latitude.toRadians();
 var longitude_radian = longitude.toRadians();
 
 */
if ( typeof( Number.prototype.toRadians ) === "undefined" || !Number.prototype.toRad ) {
  Number.prototype.toRadians = function() {
   // todo better int handling for the calculation to ensure is truly a number
   return this * Math.PI / 180;
  }
}