# Find the radius and diameter when given the area

In this lesson, we will learn how to find the radius or diameter of a circle when given the area. This lesson will involve rearranging the formula for the area of a circle.

Quiz:

# Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

Q1.Find the area of the circle in terms of π. 1/4

Q2.Find the area of the circle to three significant figures. 2/4

Q3.Find the area of the circle to 3 significant figures. 3/4

Q4.Find the area in terms of π. 4/4

Quiz:

# Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

Q1.Find the area of the circle in terms of π. 1/4

Q2.Find the area of the circle to three significant figures. 2/4

Q3.Find the area of the circle to 3 significant figures. 3/4

Q4.Find the area in terms of π. 4/4

# Video

Click on the play button to start the video. If your teacher asks you to pause the video and look at the worksheet you should:

• Click "Close Video"
• Click "Next" to view the activity

Your video will re-appear on the next page, and will stay paused in the right place.

# Worksheet

These slides will take you through some tasks for the lesson. If you need to re-play the video, click the ‘Resume Video’ icon. If you are asked to add answers to the slides, first download or print out the worksheet. Once you have finished all the tasks, click ‘Next’ below.

Quiz:

# Find the Radius and Diameter when given the Area

Don’t worry if you get a question wrong! Forgetting is an important step in learning. We will recap next lesson.

Q1.What is missing from this rearranged formula? 1/4

Q2.What will this formula find? 2/4

Q3.Find the radius of this circle to three significant figures. 3/4

Q4.The area of a circle is 20 cm squared. What is the diameter to 3 significant figures? 4/4

Quiz:

# Find the Radius and Diameter when given the Area

Don’t worry if you get a question wrong! Forgetting is an important step in learning. We will recap next lesson.

Q1.What is missing from this rearranged formula? 1/4

Q2.What will this formula find? 2/4

Q3.Find the radius of this circle to three significant figures. 3/4

Q4.The area of a circle is 20 cm squared. What is the diameter to 3 significant figures? 4/4

# Lesson summary: Find the radius and diameter when given the area

## Time to move!

Did you know that exercise helps your concentration and ability to learn?

For 5 mins...

Move around:
Jog

On the spot:
Dance