When you click Relative, this World dialog box appears and you will be prompted to enter the relative values.
Cartesian Coordinates
The X, Y, and Z values that you enter will be the distances from a location you will later select to the new position you are locating.
Polar Coordinates
Radius
The linear distance along the defined angle from a point you will later select to the new position you are locating.
Angle
This is the angle located in standard position with vertex at a point you select later, along whose terminal side will be the new position you are locating at a distance equal to the radius.