# Sphere

The sphere is a three-dimensional shape. A sphere is round, has no edges, and is a solid shape. The sphere is three dimensional solid, that has surface area and volume.The playing ball, balloon, and even light bulbs are examples of sphere shape.

### Important Facts on Sphere

- A sphere is perfectly symmetrical
- A sphere is not a polyhedron
- All the points on the surface are equidistant from the center
- A sphere does not have a surface of centers
- A sphere has constant mean curvature
- A sphere has a constant width and circumference.

**Important Elements of a Sphere Shape**

Radius: The distance between the center of a sphere and its surface is called the radius. It is denoted by the letter *r*.

**Diameter: **Think of the diameter as the longest straight line you can put inside a sphere. The diameter passes through the center and joins two opposite points on the surface of a sphere. Its value is always twice that of the radius. It is denoted by the letter *d*.* *The formula to calculate the diameter of a **sphere** is 2*r*.* **d =** 2r*

**Circumference: **The circumference of a sphere can be defined as the greatest cross-section of a circle that we can cut from a sphere. The formula for the circumference of a sphere is given by 2 *r.*

*C=** 2 π r, where r is the radius of the circle and π (pi) is approximately 3.14.*

**Surface Area: **The surface area of a sphere is the total area of its rolling surface. The formula to calculate the surface area of a sphere is given by,

*SA = **4 $\mathrm{\pi}$${r}^{2}$***, **where r is the radius of the circle and π(pi) is approximately 3.14.

It is measured in square units.

**Volume: **The volume of a sphere can be defined as the capacity of a liquid that the sphere would hold if it were completely hollow.

*V = $\frac{4}{3}\mathrm{\pi}$${r}^{3}$ *