# Radius of a Sphere

## Method #1 – Radius from the volume

### Formula – How to calculate the radius of a sphere from the volume

Radius = 3√((3 x Volume) ÷ (4 x π))

##### Example

A sphere has a volume of 10

Radius = 3√((3 x 10) ÷ (4 x π))

Radius = 3√((3 x 10) ÷ (4 x 3.14159))

Radius = 3√(30 ÷ 12.56636)

## Method #2 – Radius from the surface area

### Formula – How to calculate the radius of a sphere from the surface area

Radius = √(Area ÷ 4π)

##### Example

A sphere has a surface area of 10

Radius = √(10 ÷ (4 x 3.14159))

Radius = √(10 ÷ 12.56636)

## Method #3 – Radius from the diameter

### Formula – How to calculate the radius of a sphere from the diameter

Radius = Diameter ÷ 2

##### Example

A sphere has a diameter of 10

Radius = 10 ÷ 2 = 5

## Method #4 – Radius from the circumference

### Formula – How to calculate the radius of a sphere from the circumference

Radius = Circumference ÷ π ÷

##### Example

A sphere has a circumference of 100

Radius = 100 ÷ π ÷ 2

Radius = 100 ÷ 3.14159 ÷ 2