  One of the couple of translatable radii of an operator in the direction of
another operator introduced in earlier work[13] is studied in details. A
necessary and sufficient condition for a unit vector f to be a stationary
vector of the generalized eigenvalue problem $ Tf = \lambda A f $ is obtained.
Finally a theorem of Williams[16] is generalized to obtain a translatable
radius of an operator in the direction of another operator.
