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 circularArc = EllipticArcBuilderEx.CreateEllipticArcSegment(centerPt, 0, Math.PI / 2, 0, 1, 0.5);

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

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