A sphere is a three-dimensional geometric shape that is perfectly symmetrical around its center. Every point on the surface of a sphere is the same distance from its center. This distance is known as the radius of the sphere. For example, in the case of a sphere with radius , any point on its surface is exactly units away from its center.

The surface area of a sphere is calculated using this formula:

The volume of a sphere is calculated using the formulas:

A circle is a basic shape used throughout mathematics. A circle is defined as a shape where every point along its perimeter is an equal distance from its center.

Volume is a measure of the amount of space that an object or substance occupies. In mathematics, especially in solid geometry, it is used to determine the capacity or space within a 3-dimensional object.