C1GaugeSegment shows a part of a circle as it is shown at the below images. The StartAngle and SweepAngle properties are in degrees. They don't take the CornerRadius into account (work as if the CornerRadius is 0). The InnerRadius property can be positive, negative, or 0 (default).

[Settings for the above shape: StartAngle = -80, SweepAngle = 160, OuterRadius = 100]

[Settings for the above shape: StartAngle = -115, SweepAngle = 230, OuterRadius = 100, InnerRadius = 110]

[Settings for the above shape: StartAngle = -115, SweepAngle = 230, CornerRadius = 20, OuterRadius = 100, InnerRadius = 160]

[Settings for the above shape: StartAngle = -80, SweepAngle = 160, CornerRadius = 20, OuterRadius = 100, InnerRadius = -200]