Find Areas of Circles Using Their Radiuses Worksheet

This worksheet is about finding the areas of circles.

You must learn this important formula for a circle of radius, r :

Area of a circle = π r²

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...

In this activity, you will need to use a scientific calculator to calculate the answers. You can use one online if you do not have one in your home.

Example

Find the area of a circle of radius 6 cm.

Answer

Area = π r² = π × 6² = π × 36 = 113.1 cm² (1 dp)

Remember, in this activity, you need to use a scientific calculator to calculate pi correctly, you can access one of these online.

Find the area of a circle with a radius of 10 cm in cm².

Write the number to 1 decimal place.

Find the area of a circle with a radius of 2 cm in cm².

Just write the number to 1 decimal place.

Find the area of a circle with a radius of 5 cm in cm².

Write the number to 1 decimal place.

Find the area of a circle with a radius of 6 cm in cm².

Write the number to 1 decimal place.

Find the area of a circle with a radius of 16 cm in cm².

Write your answer to 1 decimal place.

Find the area of a circle with a radius of 25 cm in cm².

Write your answer to 1 decimal place.

Find the area of a circle with a radius of 5.8 cm in cm².

Write your answer to 1 decimal place.

Find the area of a circle with a radius of 12.4 cm in cm².

Write your answer to 1 decimal place.

Find the area of a circle with a radius of 0.5 cm in cm².

Write your answer to 1 decimal place.

Find the area of a circle with a radius of 3.99 cm in cm².

Write your answer to 1 decimal place.

ANSWERS

Question 1

Find the area of a circle with a radius of 10 cm in cm².

Write the number to 1 decimal place.

CORRECT ANSWER

EDDIE SAYS

Did you read the question carefully? Did you remember to give your answer to one decimal place? If you didn't do this, you may have been marked as incorrect. If you were, make sure you remember for the next questions.

Area = π x r²

Area = π x 10²

ANSWERS

Question 2

Find the area of a circle with a radius of 2 cm in cm².

Just write the number to 1 decimal place.

CORRECT ANSWER

EDDIE SAYS

Another reminder to read the question carefully? Remember to give your answer to one decimal place. If you didn't do this, you may have been marked as incorrect. If you were, make sure you remember for the next questions.

Area = π x r²

Area = π x 2²

ANSWERS

Question 3

Find the area of a circle with a radius of 5 cm in cm².

Write the number to 1 decimal place.

CORRECT ANSWER

EDDIE SAYS

We're sure you've remembered, but just in case, you needed to give your answer to 1 decimal place. Your answer needs to be to one decimal place. Did you do it?

Area = π x r²

Area = π x 5²

ANSWERS

Question 4

Find the area of a circle with a radius of 6 cm in cm².

Write the number to 1 decimal place.

CORRECT ANSWER

EDDIE SAYS

Did you remember to give your answer to one decimal place? If you didn't you will have been marked as incorrect, this can cost you marks in a test. Is this formula now becoming second nature? π r ²

Area = π x r²

Area = π x 6²

ANSWERS

Question 5

Find the area of a circle with a radius of 16 cm in cm².

Write your answer to 1 decimal place.

CORRECT ANSWER

EDDIE SAYS

Did you remember to give your answer to one decimal place? If you didn't you will have been marked as incorrect, this can cost you marks in a test.

Area = π x r²

Area = π x 16²

ANSWERS

Question 6

Find the area of a circle with a radius of 25 cm in cm².

Write your answer to 1 decimal place.

CORRECT ANSWER

EDDIE SAYS

Is this becoming easier? It's just a case of remembering the formula and committing it to memory!

Area = π x r²

Area = π x 25²

ANSWERS

Question 7

Find the area of a circle with a radius of 5.8 cm in cm².

Write your answer to 1 decimal place.

CORRECT ANSWER

EDDIE SAYS

You know what to do now! Just keep applying that formula and reading the questions carefully, practice makes perfect!

Area = π x r²

Area = π x 5.8²

ANSWERS

Question 8

Find the area of a circle with a radius of 12.4 cm in cm².

Write your answer to 1 decimal place.

CORRECT ANSWER

EDDIE SAYS

You'll be saying this formula in your sleep! π r ² that's all there is to it!

Area = π x r²

Area = π x 12.4²

ANSWERS

Question 9

Find the area of a circle with a radius of 0.5 cm in cm².

Write your answer to 1 decimal place.

CORRECT ANSWER

EDDIE SAYS

We're sure we don't need to remind you of the formula now, but just in case, π r ²

Area = π x r²

Area = π x 0.5²

ANSWERS

Question 10

Find the area of a circle with a radius of 3.99 cm in cm².

Write your answer to 1 decimal place.

CORRECT ANSWER

EDDIE SAYS

Did you get this last one right?

Area = π x r²

Area = π x 3.99²

Well done for completing another activity, hopefully you are feeling much more confident now with calculating the area of a circle! Keep up the great work!