ArcGIS Pro 2.7 API Reference Guide
StartPoint Property (Segment)
Example 

ArcGIS.Core.Geometry Namespace > Segment Class : StartPoint Property
Gets the start point of this instance.
Syntax
public MapPoint StartPoint {get;}
Public ReadOnly Property StartPoint As MapPoint
Example
// retrieve the bezier curve's control points
CubicBezierSegment cb = CubicBezierBuilder.CreateCubicBezierSegment(bezierSegment);
MapPoint startPt = cb.StartPoint;
Coordinate2D ctrlPt1 = cb.ControlPoint1;
Coordinate2D ctrlPt2 = cb.ControlPoint2;
MapPoint endPt = cb.EndPoint;

bool isCurve = cb.IsCurve;
double len = cb.Length;
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

Segment Class
Segment Members