## PI Formula

The PI formula is related to the diameter and circumference of a circle. The formula is used to find out the value of PI if the diameter and circumference of the circle are given. The PI is a Latin word that is represented with the help of a symbol ‘π’ and PI is the ratio of the circumference of the circle to the diameter of the circle. In the decimal form, the value of PI is estimated to be 3.14169…. and this value cannot be transformed into a proper decimal unit.

PI is an irrational number that cannot be transformed into a common fraction. The exact value of PI is non-terminating, with no repeating decimal, and can be calculated with help of the PI formula. No matter how big or small the circle is, the diameter must be divided by the circumference and the result is π. PI formula can be expressed as

Pi(π) = Circumference/Diameter

## Other PI formulas

Other geometry formulas have PI other than the above one. They are as follows: –

The perimeter of the Circle = 2πr

Area of Circle = πr2

The volume of the sphere = 4/3 πr2

The surface area of the sphere = 4πr2

Here, r means the radius

### Solved Examples

**Example 1:**

Riya measured the perimeter of a circular pipe which was 88cm. Now calculate the diameter of the same pipe with help of the PI formula.

Given, that the perimeter of the pipe = 88

Using the PI formula,

π = circumference/diameter

3.14 = 88/diameter

Diameter = 28.02 inches = 28 inches approx.

**Example 2:**

The diameter of a circular park is 200 inches. With help of the PI, the formula finds out how much distance it can cover if it walked exactly 1 round around the boundary.

Diameter = 200 inches

Using the PI formula,

π = circumference/diameter

3.14 = circumference/200

Circumference= 628 inches