public double ConvertFromRadians( 
   double radians
)

// convert 45 degrees to radians
double radians = AngularUnit.Degrees.ConvertToRadians(45);

// convert PI to degrees
double degrees = AngularUnit.Degrees.ConvertFromRadians(Math.PI);

try
{
  // create a Grad unit
  var grad = AngularUnit.CreateAngularUnit(9105);
  string unitName = grad.Name;                        // Grad
  double conversionFactor = grad.ConversionFactor;    // 0.015708
  double radiansPerUnit = grad.RadiansPerUnit;
  int factoryCode = grad.FactoryCode;                 // 9105

  // convert 10 grads to degrees
  double val = grad.ConvertTo(10, AngularUnit.Degrees);

  // convert 10 radians to grads
  val = grad.ConvertFromRadians(10);
}
catch (ArgumentException)
{
  // ArgumentException will be thrown by CreateAngularUnit in the following scenarios
  // - if the factory code used is a non-angular factory code  (i.e. it corresponds to square meters which is an area unit code)
  // - if the factory code used is invalid (i.e. it is negative or doesn't correspond to any factory code)
}