The starting angle, in radians.
Sample Code
This code sets the starting angle to -1.57 radians:
Var a As New ArcShape
a.Height = 150
a.Width = 150
a.Rotation = 0.90
a.ArcAngle = 1.57
a.StartAngle = -1.57
a.Border = 100
a.BorderColor = &c0000ff
a.BorderWidth = 2.75
a.Fill = 50
a.FillColor = RGB(255,0,127)
g.DrawObject(a, 100, 100)