Le théorème de Pythagore est un outil mathématique très puissant... Show more
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Updated Apr 15, 2026
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Comprendre et Appliquer le Théorème de Pythagore
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Théorème de Pythagore
Le théorème de Pythagore est une règle qui s'applique uniquement aux triangles rectangles. Il nous dit que le carré de l'hypoténuse (le côté opposé à l'angle droit) est égal à la somme des carrés des deux autres côtés.
Dans un triangle rectangle, si l'hypoténuse mesure c et les deux autres côtés mesurent a et b, alors : a² + b² = c².
💡 Ce théorème est super pratique dans la vie quotidienne ! Il nous permet de calculer des distances, de vérifier si des angles sont droits, et même d'aider les constructeurs à bâtir des maisons stables.
L'échelle du peintre
Imagine un peintre qui utilise une échelle de 5m pour atteindre un mur. L'échelle forme un triangle rectangle avec le sol et le mur.
Si le pied de l'échelle est à 3m du mur, à quelle hauteur l'échelle touchera-t-elle le mur? Avec le théorème de Pythagore, on peut écrire : 3² + h² = 5². En calculant, on trouve que h = 4m.
Si le peintre doit atteindre 4,8m de hauteur, il faudra placer l'échelle à seulement 1,4m du mur. C'est facile à calculer avec la formule : d² + 4,8² = 5².
⚠️ Attention ! Pour que ces calculs soient corrects, il faut absolument que le mur et le sol forment un angle droit. Sinon, le théorème de Pythagore ne s'applique pas !
La serre triangulaire
Un jardinier veut construire une serre avec une façade en forme de triangle isocèle (deux côtés égaux). La base mesure 6m et la hauteur 2,5m.
Pour trouver la longueur des deux côtés égaux (AB et AC), on utilise d'abord le fait que le point H est au milieu de la base BC. Donc BH = 3m.
On peut maintenant utiliser le théorème de Pythagore dans le triangle ABH : AB² = AH² + BH² = 2,5² + 3² = 6,25 + 9 = 15,25. Donc AB ≈ 3,9m.
🌱 Dans un triangle isocèle, la hauteur qui part du sommet principal est aussi une médiane et forme un angle droit avec la base. C'est pour ça que le théorème de Pythagore fonctionne ici !
Vérifier si un mur est droit
Un architecte doit vérifier si un mur est bien perpendiculaire au sol. Il marque un point A à 3m du pied du mur et un point B sur le mur à 4m de hauteur.
Si le mur est parfaitement droit, la distance AB devrait être exactement de 5m . C'est comme une version géante du triangle 3-4-5 !
Si l'architecte mesure 5,1m au lieu de 5m, cela signifie que le mur n'est pas parfaitement perpendiculaire au sol. Un petit écart peut sembler insignifiant, mais c'est très important !
🏗️ Un mur qui n'est pas d'aplomb (pas perpendiculaire au sol) peut causer des problèmes de stabilité, rendre difficile l'installation de fenêtres ou de portes, et même enfreindre les règles de construction. La précision, c'est la clé d'une construction solide !
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Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
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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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. 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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. 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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
Comprendre et Appliquer le Théorème de Pythagore
Le théorème de Pythagore est un outil mathématique très puissant qui nous aide à calculer les distances dans les triangles rectangles. Tu vas découvrir comment ce théorème s'applique dans des situations concrètes comme positionner une échelle, construire une serre, ou... Show more
Théorème de Pythagore
Le théorème de Pythagore est une règle qui s'applique uniquement aux triangles rectangles. Il nous dit que le carré de l'hypoténuse (le côté opposé à l'angle droit) est égal à la somme des carrés des deux autres côtés.
Dans un triangle rectangle, si l'hypoténuse mesure c et les deux autres côtés mesurent a et b, alors : a² + b² = c².
💡 Ce théorème est super pratique dans la vie quotidienne ! Il nous permet de calculer des distances, de vérifier si des angles sont droits, et même d'aider les constructeurs à bâtir des maisons stables.
Sign up to see the contentIt's free!
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Improve your grades
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L'échelle du peintre
Imagine un peintre qui utilise une échelle de 5m pour atteindre un mur. L'échelle forme un triangle rectangle avec le sol et le mur.
Si le pied de l'échelle est à 3m du mur, à quelle hauteur l'échelle touchera-t-elle le mur? Avec le théorème de Pythagore, on peut écrire : 3² + h² = 5². En calculant, on trouve que h = 4m.
Si le peintre doit atteindre 4,8m de hauteur, il faudra placer l'échelle à seulement 1,4m du mur. C'est facile à calculer avec la formule : d² + 4,8² = 5².
⚠️ Attention ! Pour que ces calculs soient corrects, il faut absolument que le mur et le sol forment un angle droit. Sinon, le théorème de Pythagore ne s'applique pas !
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La serre triangulaire
Un jardinier veut construire une serre avec une façade en forme de triangle isocèle (deux côtés égaux). La base mesure 6m et la hauteur 2,5m.
Pour trouver la longueur des deux côtés égaux (AB et AC), on utilise d'abord le fait que le point H est au milieu de la base BC. Donc BH = 3m.
On peut maintenant utiliser le théorème de Pythagore dans le triangle ABH : AB² = AH² + BH² = 2,5² + 3² = 6,25 + 9 = 15,25. Donc AB ≈ 3,9m.
🌱 Dans un triangle isocèle, la hauteur qui part du sommet principal est aussi une médiane et forme un angle droit avec la base. C'est pour ça que le théorème de Pythagore fonctionne ici !
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Vérifier si un mur est droit
Un architecte doit vérifier si un mur est bien perpendiculaire au sol. Il marque un point A à 3m du pied du mur et un point B sur le mur à 4m de hauteur.
Si le mur est parfaitement droit, la distance AB devrait être exactement de 5m . C'est comme une version géante du triangle 3-4-5 !
Si l'architecte mesure 5,1m au lieu de 5m, cela signifie que le mur n'est pas parfaitement perpendiculaire au sol. Un petit écart peut sembler insignifiant, mais c'est très important !
🏗️ Un mur qui n'est pas d'aplomb (pas perpendiculaire au sol) peut causer des problèmes de stabilité, rendre difficile l'installation de fenêtres ou de portes, et même enfreindre les règles de construction. La précision, c'est la clé d'une construction solide !
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
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.
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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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. 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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. 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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user