ArcGIS Pro 2.7 API Reference Guide
CreateEllipticArcSegment(Double,Double,Coordinate2D,Double,SpatialReference) Method
Example 

ArcGIS.Core.Geometry Namespace > EllipticArcBuilder Class > CreateEllipticArcSegment Method : CreateEllipticArcSegment(Double,Double,Coordinate2D,Double,SpatialReference) Method
The angle, measured from a horizontal line through the circular arc's center point, that defines where the arc starts.
The angle which describes the span of the circular arc.
The center point of the embedded circle.
The distance from the center of the embedded circle to the perimeter.
(Optional) The spatial reference of the arc. The default value is null.
Convenience method to create a new instance of the EllipticArcSegment class. The new instance will be a circular arc.
Syntax
Public Overloads Shared Function CreateEllipticArcSegment( _
   ByVal startAngle As Double, _
   ByVal centralAngle As Double, _
   ByVal centerPt As Coordinate2D, _
   ByVal radius As Double, _
   Optional ByVal spatialReference As SpatialReference _
) As EllipticArcSegment

Parameters

startAngle
The angle, measured from a horizontal line through the circular arc's center point, that defines where the arc starts.
centralAngle
The angle which describes the span of the circular arc.
centerPt
The center point of the embedded circle.
radius
The distance from the center of the embedded circle to the perimeter.
spatialReference
(Optional) The spatial reference of the arc. The default value is null.

Return Value

Example
// Construct a circular arc with center point at (0, 0), from angle = 0, 
// central angle = pi/2, radius = 1.
// Use a builder convenience method or use a builder constructor.

SpatialReference sr4326 = SpatialReferences.WGS84;
Coordinate2D centerPt = new Coordinate2D(0, 0);
double fromAngle = 0;
double centralAngle = Math.PI / 2;
double radius = 1;

// Builder convenience methods don't need to run on the MCT.
EllipticArcSegment circularArc = EllipticArcBuilder.CreateEllipticArcSegment(fromAngle, centralAngle, centerPt, radius, sr4326);

// Builder constructors need to run on the MCT.
ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
{
  using (EllipticArcBuilder cab = new EllipticArcBuilder(fromAngle, centralAngle, centerPt, radius, sr4326))
  {
    // do something with the builder

    EllipticArcSegment otherCircularArc = cab.ToSegment();
  }
});
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

EllipticArcBuilder Class
EllipticArcBuilder Members
Overload List