A sphere is a solid of geometry. The surface of the sphere, the periphery, consists of an infinite number of consecutive points, all positioned at the same distance from the spheres center point.
The size of the sphere is defined by the radius, the distance between the center point and the periphery.
The diameter of the sphere is the length of a line between two points on the periphery passing through the sphere’s center. The diameter is twice the radius.
Examples of spheres
Well-known examples of spheres, or at least nearly spherical shapes, are the earth, billiard balls and soccer balls.