Circle of a sphere the Equator the only great circle. By contrast, all meridians of longitude, paired with their opposite meridian in the other hemisphere, form great circles. The diameter of the sphere which passes through the center of the circle is called its axis and the endpoints of this diameter are called its poles. A circle of a sphere can also be defined as the set of points at a given angular distance from a given pole. When the intersection of a sphere and a plane is not empty or a single point, it is a circle. This can be seen as follows:
Inversion in a sphere in this article are dependent on three simple ideas: (See fig 1) (See fig 2) (See fig 3) Note 4: Generally, the inverse of a line is a circle through the centre of reference. Note 5: Generally, the inverse of a plane is a sphere through the centre of reference. (See fig 4) (See fig 5) Note 6: Generally the inverse of a sphere is a sphere (Cf Figs 3, 4, 5) Note 7: Generally the inverse of a circle is a circle. Inversion in a sphere In geometry, inversion in a sphere is a transformation of Euclidean space that