# 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 2r.  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 π 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}$ . It is measured in cubic units.