°A regular three-dimensional object in which every cross-section is a circle; the figure described by the revolution of a semi-circle about its diameter.
°The set of all points in three-dimensionalEuclidean space (or -dimensional space, in topology) that are a fixed distance from a fixed point.
°A regular three-dimensional object in which every cross-section is a circle; the figure described by the revolution of a semi-circle about its diameter.
°The set of all points in three-dimensionalEuclidean space (or -dimensional space, in topology) that are a fixed distance from a fixed point.