## Sphere formula

A perfectly symmetrical 3 – Dimensional circular shaped object is a Sphere. The line that connects from the center to the boundary is called radius of the square. You will find a point equidistant from any point on the surface of a sphere. The longest straight line that passes through the center of the sphere is called the diameter of the sphere. It is twice the length of the radius of the sphere.

\[\large Diameter\;of\;a\;sphere=2r\]

\[\large Circumference\;of\;a\;sphere=2\pi r\]

\[\large Surface\;area\;of\;a\;sphere=4\pi r^{2}\]

\[\large Volume;of\;a\;sphere=\frac{4}{3}\: \pi r^{3}\]

### Solved Example

**Question: **Calculate the diameter, circumference, surface area and volume of a sphere of radius 9 cm ?

**Solution:**

Given,

**r = 7 cm**

**Diameter of a sphere
**=2r

= 2 × 9

=18 cm

**Circumference of a sphere**

= 2πr

= 2 × π × 9

= 56.54 cm

**Surface area of a sphere**

$4\pi r^{2}$

$4\times \pi \times 9^{2}$

$4\times \pi \times 81$

= 1017.87 cm

**Volume of a sphere**

$\frac{4}{3}\;\pi r^{3}$

$\frac{4}{3}\;\pi 9^{3}$

= 338.2722 cm

More topics in Sphere Formula | |

Volume of a Sphere Formula | Surface Area of a Sphere Formula |