# Sphere Shape

By the end of this lesson, you will be able to

- describe sphere.
- explain area of sphere.
- identify raius of sphere
- derive the formula for the volume of sphere.

## Sphere

The solid produced by rotating a circle around its diameter keeping fixed is called sphere. A sphere is a smoothly and perfectly round 3-dimensional shape.

A sphere showing its radius and curved surface.

Another way, a sphere is a round solid object formed by the set of all points that are equidistant from a fixed point.

The equidistant means the distant from a fixed point to all the points of the set is constant. The fixed point is called the center and constant distant

is called the radius of the sphere.

### Sphere Example

### Area of sphere

Let r be the radius and A be the area of sphere.

∴ A = 4πr^{2} square unit

A sphere is showing its surface.

If r and A are the radius and surface area of sphere respectively,

A = 4πr^{2} square unit

### Volume of sphere

Suppose, r is the radius and V is the volume of sphere.

∴ V = 43 πr^{3} cubic unit

If the raddius and volume of sphere are r and V respectively,

V = 43 πr^{3} cubic unit