  In this study, we give the relationships between the conical curvatures of
ruled surfaces drawn by the unit vectors of the ruling, central normal and
central tangent of a regular ruled surface in the Euclidean -space. We obtain
the differential equations characterizing slant ruled surfaces and if the
reference ruled surface is a slant ruled surface, we give some conditions for
the surfaces drawn by the central normal and the central tangent vectors to be
slant ruled surfaces.
