[Center, Radius] command generates a circle with the center and the radius specified.
While
"Specify the center of the circle"
prompt is displayed, specify the center of the circle to generate.
Pressing "A" key, the command generates a circle that touches the existing curves vertically.
Pressing"V" key, the command generates a circle that is perpendiculat to the active CPlane.
While
"Radius Specify"
prompt is displayed, specify the radius of the circle to generate, by inputting
a point the circle passes through.
Pressing"R"key, a dialogue to input radius is shown