Radius Of Gyration

The radius of gyration of body is 18cm when it is rotating about an axis passing through centre of mass of body. If radius of gyration of same body is 30cm about a parallel axis to first axis then, perpendicular distance between two parallel axes is

A ballet dancer is rotating at angular velocity omega on smooth horizontal floor. The ballet dancer folds his body close to his axis of rotation by which his radius of gyration decreases by 1//4^(th) of his initial radius of gyration, his final angular velocity is