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Maths
3 Dec 2025
95
2 pages
shai @kroshai
Need to calculate areas for your maths exams? These essential formulas will help you work out the space... Show more
You'll use these three formulas constantly in your maths lessons, so getting them sorted now will save you loads of time later.
For squares and rectangles, it's dead simple just multiply the base by the height. A square with 5cm sides? That's 5 × 5 = 25cm². A rectangle that's 8cm by 3cm? That's 8 × 3 = 24cm².
Triangles need a slightly different approach because they're basically half of a rectangle. Take the base, multiply by the perpendicular height, then divide by 2. So a triangle with a 6cm base and 4cm height gives you (6 × 4) ÷ 2 = 12cm².
Quick Tip Always check you're using the perpendicular height for triangles - it's the line that goes straight down from the top to the base, not the slanted side!
These shapes might look trickier, but once you know the formulas, they're just as straightforward as the basic ones.
A trapezium has two parallel sides of different lengths. Add those two parallel sides together, multiply by the height, then divide by 2. The formula × height ÷ 2 works every time.
Parallelograms are like rectangles that have been pushed sideways. You still use base × perpendicular height - just make sure you measure the height at a right angle, not along the slanted edge.
For a kite, you're looking at the two diagonals (the lines that cross inside). Multiply the length by the height, then divide by 2 - it's similar to finding a triangle's area.
Exam Success These formulas usually appear on your exam paper, but practising them now means you won't waste precious time looking them up during tests!
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
1
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore essential GCSE maths formulas including area, volume, trigonometry, and probability. This comprehensive summary covers key concepts such as the Pythagorean theorem, sine and cosine rules, and quadratic equations, making it an invaluable resource for exam preparation.
MathsEnhance your exam readiness with this comprehensive practice paper for the Edexcel Level 1/Level 2 GCSE (9-1) Mathematics Higher Tier. This resource includes answered questions covering key concepts such as trigonometry, probability, statistics, and geometry. Ideal for students preparing for their GCSE exams, this paper helps reinforce understanding and application of mathematical principles.
MathsExplore the essential formulas and classifications of triangles in this concise summary. Learn about equilateral, scalene, and isosceles triangles, and how to calculate their area using the formula: Area = 1/2 × Base × Height. Perfect for quick revision and understanding triangle geometry.
MathsPrepare for your GCSE Higher Mathematics exam with this comprehensive mock exam set. This resource covers key topics such as simplifying rational expressions, solving inequalities, geometric transformations, and more. Ideal for students looking to practice and improve their understanding of essential mathematical concepts. Includes detailed solutions and explanations for each question.
MathsComprehensive answers and explanations for GCSE Maths Paper 1, covering key concepts such as arithmetic sequences, probability, graph types, and statistical analysis. Ideal for students preparing for their exams. Includes worked examples and step-by-step solutions.
MathsMaster the process of determining the Nth term in quadratic sequences through first and second differences. This summary covers essential techniques, including N² calculations and difference tables, to enhance your understanding of polynomials and sequences.
MathsApp Store
Google 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 S
iOS 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 Klich
Android 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.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
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 S
iOS 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 Klich
Android 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.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
shai
@kroshai
Need to calculate areas for your maths exams? These essential formulas will help you work out the space inside different shapes quickly and accurately.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
You'll use these three formulas constantly in your maths lessons, so getting them sorted now will save you loads of time later.
For squares and rectangles, it's dead simple: just multiply the base by the height. A square with 5cm sides? That's 5 × 5 = 25cm². A rectangle that's 8cm by 3cm? That's 8 × 3 = 24cm².
Triangles need a slightly different approach because they're basically half of a rectangle. Take the base, multiply by the perpendicular height, then divide by 2. So a triangle with a 6cm base and 4cm height gives you (6 × 4) ÷ 2 = 12cm².
Quick Tip: Always check you're using the perpendicular height for triangles - it's the line that goes straight down from the top to the base, not the slanted side!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
These shapes might look trickier, but once you know the formulas, they're just as straightforward as the basic ones.
A trapezium has two parallel sides of different lengths. Add those two parallel sides together, multiply by the height, then divide by 2. The formula × height ÷ 2 works every time.
Parallelograms are like rectangles that have been pushed sideways. You still use base × perpendicular height - just make sure you measure the height at a right angle, not along the slanted edge.
For a kite, you're looking at the two diagonals (the lines that cross inside). Multiply the length by the height, then divide by 2 - it's similar to finding a triangle's area.
Exam Success: These formulas usually appear on your exam paper, but practising them now means you won't waste precious time looking them up during tests!
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
1
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore essential GCSE maths formulas including area, volume, trigonometry, and probability. This comprehensive summary covers key concepts such as the Pythagorean theorem, sine and cosine rules, and quadratic equations, making it an invaluable resource for exam preparation.
MathsEnhance your exam readiness with this comprehensive practice paper for the Edexcel Level 1/Level 2 GCSE (9-1) Mathematics Higher Tier. This resource includes answered questions covering key concepts such as trigonometry, probability, statistics, and geometry. Ideal for students preparing for their GCSE exams, this paper helps reinforce understanding and application of mathematical principles.
MathsExplore the essential formulas and classifications of triangles in this concise summary. Learn about equilateral, scalene, and isosceles triangles, and how to calculate their area using the formula: Area = 1/2 × Base × Height. Perfect for quick revision and understanding triangle geometry.
MathsPrepare for your GCSE Higher Mathematics exam with this comprehensive mock exam set. This resource covers key topics such as simplifying rational expressions, solving inequalities, geometric transformations, and more. Ideal for students looking to practice and improve their understanding of essential mathematical concepts. Includes detailed solutions and explanations for each question.
MathsComprehensive answers and explanations for GCSE Maths Paper 1, covering key concepts such as arithmetic sequences, probability, graph types, and statistical analysis. Ideal for students preparing for their exams. Includes worked examples and step-by-step solutions.
MathsMaster the process of determining the Nth term in quadratic sequences through first and second differences. This summary covers essential techniques, including N² calculations and difference tables, to enhance your understanding of polynomials and sequences.
MathsApp Store
Google 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 S
iOS 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 Klich
Android 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.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
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 S
iOS 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 Klich
Android 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.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Sociology