When you create a conic arc, a dimension scheme is automatically applied to it. This scheme defines a set of weak dimensions for the rho value and the location or tangency angles of the end points, or both. Alternatively, you can dimension the conic arc by aligning it with up to five points.

As you add each constraint, weak dimensions are removed from the sketch. If any of the constraints conflict with a strong dimension, the Resolve Sketch dialog box opens. Remove the conflicting constraint or dimension.