## The Lesson

The diameter of a circle is found from the area of a circle using the formula: In this formula,**A**is the area of the circle. The image below shows what we mean by finding the diameter from the circumference:

## How to Find the Diameter from the Area

Finding the diameter from the area is easy.## Question

What is the diameter of the circle, with area 50 cm^{2}, below?

## Step-by-Step:

# 1

Start with the formula:

Diameter = 2√ (

^{A}⁄_{π})**Don't forget:**√ means square root, / means ÷**and**π is pi (≈ 3.14)# 2

Substitute the area into the formula. In our example, A = 50.

Diameter = √ (^{50}⁄_{π})

Diameter = √ (50 ÷ π)

Diameter = √ (50 ÷ 3.14)

Diameter = √ 16 cm

Diameter = 4 cm