public void GetAxes( 
   out double semiMajorAxis,
   out double semiMinorAxis
)

{
  // Construct an elliptic arc centered at (1,1), startAngle = 0, centralAngle = PI/2, 
  // rotationAngle = 0, semiMajorAxis = 1, minorMajorRatio = 0.5.
  // Use a builderEx convenience method or use a builderEx constructor.

  Coordinate2D centerPt = new Coordinate2D(1, 1);

  // BuilderEx convenience methods don't need to run on the MCT.
  ellipticArcSegment = EllipticArcBuilderEx.CreateEllipticArcSegment(centerPt, 0, Math.PI / 2, 0, 1, 0.5);

  double semiMajor;
  double semiMinor;
  ellipticArcSegment.GetAxes(out semiMajor, out semiMinor);
  // semiMajor = 1, semiMinor = 0.5

  // BuilderEx constructors don't need to run on the MCT.
  EllipticArcBuilderEx ellipticArcBuilderEx = new EllipticArcBuilderEx(centerPt, 0, Math.PI / 2, 0, 1, 0.5);
  ellipticArcBuilderEx.GetAxes(out semiMajor, out semiMinor);
  EllipticArcSegment arcSegment = ellipticArcBuilderEx.ToSegment();
}