Practise Finding the Area of a Circle

In this activity, we will be calculating the area of circles.

 

You will need a scientific calculator.

 

 

To find the area of a circle we square the radius and multiply it by pi  

What is pi (π) in numbers? 

Pi is an infinite number, and you can use a function on your calculator to input the number.

Here is the start of it  3.14159265359...

 

We write it like this in short:

Area of a circle = π r²

 

Let's look at a question.

 

Example

Find the area of a circle of radius 6 cm.

Give your answer to 1 decimal place.

 

 

Answer

Area = π r²

=  π × 6²

= π × 36

= 113.097335529 

 

We need to give our answer to 1 decimal place so we need to round up.

 

Area =  113.1 cm²  

 

Remember, in this activity, you need to use a scientific calculator to calculate pi correctly.

You can access one of these online if you do not have one.