The Circle from Center and 2 Points option allows you to create a circle of known radius and center point in a plane.
Radius
If toggled ON, the radius will be set as the specified value. If toggled OFF, the radius will be set at the distance between the first two points selected.
Start angle
For a full circle, the start angle is 0. Otherwise, specify the desired start angle.
End angle
The end angle for a full circle is 360, and for a semi-circle is 180.
Points
The first point selected is the center point of the circle. The next 2 points selected will be used to define the plane of the circle.