/// <summary>
/// Radian angle between two points from a centre.
/// </summary>
/// <param name="centre"></param>
/// <param name="start"></param>
/// <param name="end"></param>
/// <returns></returns>
public static double StartEndRadiansFromCentre(DSPoint centre, DSPoint start, DSPoint end)
{
Vertex c = ToVertex(centre);
Vertex s = ToVertex(start);
Vertex e = ToVertex(end);
return(Vertex.ArcRadAngle(c, s, e));
}
