Finding the area of a sector is like slicing a... Show more
Geometry73 views·Updated Jun 2, 2026·1 pageHow to Calculate the Area of a Sector of a Circle
Astrophel 🔥@asteriskedd
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Finding the Area of a Sector
When you need to find the area of a sector (a "pizza slice" of a circle), there's a simple three-step process to follow. Think of it as figuring out what fraction of the whole pizza you're getting!
First, calculate the area of the entire circle using the formula π × r². For example, with a circle of radius 5 cm, the area would be π × 5² = 78.5 square cm. This gives you the total "pizza" area.
Second, determine what fraction of the circle your sector represents by dividing the arc measure by 360°. In our example problem with a 120° sector, the fraction would be 120/360 = 1/3, meaning our sector is one-third of the circle.
Finally, multiply the circle's area by your fraction to find the sector area. For our example: 78.5 × 1/3 ≈ 26.17 square cm. That's it! You've found the area of your sector.
Try This! Imagine a circle with radius 8 cm and a sector with angle 90°. Before calculating, can you estimate what fraction of the circle this sector represents?
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Geometry73 views·Updated Jun 2, 2026·1 pageHow to Calculate the Area of a Sector of a Circle
Astrophel 🔥@asteriskedd
Finding the area of a sector is like slicing a pizza and figuring out how much space one piece takes up. It's a practical skill that combines circle geometry with simple fractions, and once you know the three-step process, you'll... Show more
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Finding the Area of a Sector
When you need to find the area of a sector (a "pizza slice" of a circle), there's a simple three-step process to follow. Think of it as figuring out what fraction of the whole pizza you're getting!
First, calculate the area of the entire circle using the formula π × r². For example, with a circle of radius 5 cm, the area would be π × 5² = 78.5 square cm. This gives you the total "pizza" area.
Second, determine what fraction of the circle your sector represents by dividing the arc measure by 360°. In our example problem with a 120° sector, the fraction would be 120/360 = 1/3, meaning our sector is one-third of the circle.
Finally, multiply the circle's area by your fraction to find the sector area. For our example: 78.5 × 1/3 ≈ 26.17 square cm. That's it! You've found the area of your sector.
Try This! Imagine a circle with radius 8 cm and a sector with angle 90°. Before calculating, can you estimate what fraction of the circle this sector represents?
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Most popular content in Geometry
9Most popular content
9Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5App Store
4.7/5Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan SiOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha KlichAndroid user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
AnnaiOS user