Sphere

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An image of a sphere

A sphere is a shape in space that is like the surface of a ball. Usually, the words ball and sphere mean the same thing. But in mathematics, a sphere is the surface of a ball, which is given by all the points in three dimensional space that are located at a fixed distance from the center. The distance from the center is called radius of the sphere. When the sphere is filled in with all the points inside, it called a ball.

Common things that have the shape of a sphere are are basketballs, superballs, and playground balls. The Earth and the Sun are nearly spherical, meaning sphere-shaped.

A sphere is the three-dimensional analog of a circle.

Volume[change | change source]

The volume () of a sphere is given by

where is the radius of the sphere.

Surface area[change | change source]

The surface area () of a sphere is given by

where is the radius of the sphere.

Equation of a sphere[change | change source]

In Cartesian coordinates, the equation for a sphere with a center at (, , ) is as follows:

where is the radius of the sphere.