

How to Find the Area of a Circle
Finding the area of a circle is easy.Question
What is the area of a circle with a radius of 5 cm, as shown below?
Step-by-Step:
2
Substitute the radius into the formula. In our example, r = 5.
Area = π × 52 = π × 5 × 5 = 78.5 cm2
Answer:
The area of the circle with a radius of 5 cm is 78.5 cm2."Find the Area" Widget
Here is a widget to help you learn the formulas to find the areas of different shapes.- Click on the shape you're learning about.
- Click on the pad to start.
- Follow the instructions in the bottom-left corner.
- On the last click, the formula, workings, and answer will appear in the yellow box.
- Enjoy!

How to Find the Area of a Circle Using the Diameter
The area of a circle can be found using the diameter rather than the radius. The area of a circle, using the diameter, is found using the formula:

What Is a Circle?
A circle is a shape containing a set of points that are all the same distance from a given point, its center.Radius and Diameter
The diameter of a circle is twice the length of its radius. If you are given the diameter of a circle, halve it to find the radius and put this in the formula. Alternatively, use the formula containing diameter.What Is Pi?
π is the symbol for pi. π is how many times longer a circle's circumference is than its diameter. It is the circumference divided by the diameter:
A Note on Units
The area of a circle is a length times a length, so we say its dimension is length2. (All areas are lengths squared). This affects the units used. If the radius is in cm, the area is in cm2. If it is in inches, the area is in inches2.You might also like...
Help Us Improve Mathematics Monster
- Do you disagree with something on this page?
- Did you spot a typo?
Find Us Quicker!
- When using a search engine (e.g., Google, Bing), you will find Mathematics Monster quicker if you add #mm to your search term.
Share This Page

If you like Mathematics Monster (or this page in particular), please link to it or share it with others.
If you do, please tell us. It helps us a lot!
Create a QR Code

Use our handy widget to create a QR code for this page...or any page.