# Finding the Diameter from the Area

(KS3, Year 7)

**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

## Answer:

The diameter of the circle is 4 cm.## Interactive Widget

Here is an interactive widget to help you learn about finding the diameter of a circle from its area.## Equivalent Formula for Finding the Diameter of a Circle from the Area

An equivalent formula for how to find the diameter of a circle from the area is: This is equivalent as the square root of 4 is 2.## Worksheet

This test is printable and sendable