Trojuholníky sú úžasné geometrické tvary, ktoré nájdeš všade okolo seba... Show more
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Updated Mar 17, 2026
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Trojuholníky: Typy a vlastnosti
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Základy trojuholníkov a ich označovanie
Trojuholník je rovinný útvar, ktorý má presne tri strany, tri vrcholy a tri vnútorné uhly - vždy! Je to jeden zo základných tvarov v geometrii.
Aby si sa v trojuholníkoch vyznal, musíš poznať základné označenia. Strany označujeme malými písmenami a, b, c. Vrcholy označujeme veľkými písmenami A, B, C. Uhly označujeme gréckymi písmenami α (alfa), β (beta), γ (gama).
Tu je dôležitý trik na zapamätanie: strana a je vždy oproti vrcholu A, strana b oproti vrcholu B a strana c oproti vrcholu C. Rovnako aj s uhlami!
Tip na zapamätanie: Predstav si trojuholník ako malý dom s troma rohmi - každý roh je vrchol a každá stena medzi rohmi je strana.
Triedenie trojuholníkov podle strán
Trojuholníky môžeme rozdeliť podľa toho, aké dlhé majú strany. Toto rozdelenie je veľmi jednoduché - stačí sa pozrieť na dĺžky!
Rôznostranný trojuholník má všetky tri strany rôzne dlhé. Vtedy sú aj všetky uhly rôzne veľké. Rovnoramenný trojuholník má dve strany rovnako dlhé (voláme ich ramená) a tretiu stranu nazývame základňa. Uhly pri základni sú vždy rovnaké!
Rovnostranný trojuholník je najšpeciálnejší - všetky tri strany sú rovnako dlhé a všetky tri uhly majú presne 60°. Je to akási "dokonalá" verzia trojuholníka.
Zaujímavosť: Rovnostranný trojuholník je vlastne aj rovnoramenný, pretože má aspoň dve strany rovnaké!
Triedenie trojuholníkov podľa uhlov
Teraz sa pozrieme na trojuholníky z pohľadu ich uhlov. Toto rozdelenie je super dôležité pre riešenie úloh!
Ostrouhlý trojuholník má všetky tri uhly ostré (menšie ako 90°). Pravouhlý trojuholník má jeden uhol presne 90° - strany pri tomto uhle nazývame odvesny a najdlhšiu stranu oproti pravému uhlu nazývame prepona.
Tupouhlý trojuholník má jeden uhol tupý (väčší ako 90°). Pamätaj si dôležité pravidlo: trojuholník nemôže mať dva pravé alebo dva tupé uhly - vždy len jeden!
Praktický tip: Pravé uhly nájdeš všade okolo seba - rohy stola, rohý knihy alebo rohý telefónu majú všetky 90°.
Súčet uhlov v trojuholníku - najdôležitejšie pravidlo
Tu prichádza na rad najdôležitejšie pravidlo o trojuholníkoch, ktoré si musíš zapamätať na celý život!
Súčet všetkých vnútorných uhlov v každom trojuholníku je vždy 180°. To znamená α + β + γ = 180°. Toto pravidlo platí úplně pre každý trojuholník - či už je malý alebo veľký, rovnostranný alebo rôznostranný.
Toto pravidlo ti pomôže vypočítať chýbajúci uhol, ak poznáš dva ostatné. Jednoducho odčítaš známe uhly od 180° a máš výsledok! Skvelý trik na kontrolu: vždy si spočítaj všetky tri uhly - ak ti nevyjde 180°, niekde je chyba.
Predstav si to takto: Keby si vystrihol trojuholník a odtrhol jeho rohy, potom ich priložil k sebe, vytvorili by rovnú čiaru - a to je presne 180°!
Príklady a riešenie úloh
Teraz si ukážeme, ako používať to, čo sme sa naučili, na konkrétnych príkladoch. Takto to bude na testoch!
Príklad s triedením podľa strán: Trojuholník so stranami 6 cm, 6 cm, 8 cm je rovnoramenný, pretože dve strany (6 cm) sú rovnaké. Príklad s triedením podľa uhlov: Trojuholník s uhlami 45°, 45°, 90° je pravouhlý, pretože má jeden uhol presne 90°.
Výpočet chýbajúceho uhla: Ak máš uhly α = 65° a β = 40°, chýbajúci uhol γ vypočítaš takto: γ = 180° - 65° - 40° = 75°. Vždy si skontroluj: 65° + 40° + 75° = 180° ✓
Skúšobný tip: Na testoch vždy kontroluj súčet uhlov - je to najrýchlejší způsob, ako zistiť, či máš správny výsledok!
Dôležité tipy a triky na zapamätanie
Jeden trojuholník môže patriť do viacerých skupín súčasne. Napríklad rovnostranný trojuholník je zároveň aj rovnoramenný a ostrouhlý!
Pri riešení úloh vždy používaj správne jednotky - uhly v stupňoch (°), strany v centimetroch (cm). Pomôcky ako pravítko a uhlomer ti pomôžu lepšie si predstaviť, o aký trojuholník ide.
Pamätaj si označenia: malé písmená pre strany, veľké písmená pre vrcholy, grécke písmená pre uhly. Toto ti ušetrí veľa času pri riešení úloh!
Záverečná rada: Cvič na rôznych príkladoch - čím viac úloh vyriešiš, tým istejší budeš v rozoznávaní a počítaní s trojuholníkmi!
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You can download the app from Google Play Store and Apple App Store.
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4.7/5
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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
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 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 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 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 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
Trojuholníky: Typy a vlastnosti
Trojuholníky sú úžasné geometrické tvary, ktoré nájdeš všade okolo seba - v domoch, mostoch, dokonca aj v tvojich obľúbených hračkách! Naučíš sa ich rozoznať a pochopiť ich vlastnosti, čo ti bude super užitočné nielen teraz, ale aj v ďalších ročníkoch.
Základy trojuholníkov a ich označovanie
Trojuholník je rovinný útvar, ktorý má presne tri strany, tri vrcholy a tri vnútorné uhly - vždy! Je to jeden zo základných tvarov v geometrii.
Aby si sa v trojuholníkoch vyznal, musíš poznať základné označenia. Strany označujeme malými písmenami a, b, c. Vrcholy označujeme veľkými písmenami A, B, C. Uhly označujeme gréckymi písmenami α (alfa), β (beta), γ (gama).
Tu je dôležitý trik na zapamätanie: strana a je vždy oproti vrcholu A, strana b oproti vrcholu B a strana c oproti vrcholu C. Rovnako aj s uhlami!
Tip na zapamätanie: Predstav si trojuholník ako malý dom s troma rohmi - každý roh je vrchol a každá stena medzi rohmi je strana.
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Triedenie trojuholníkov podle strán
Trojuholníky môžeme rozdeliť podľa toho, aké dlhé majú strany. Toto rozdelenie je veľmi jednoduché - stačí sa pozrieť na dĺžky!
Rôznostranný trojuholník má všetky tri strany rôzne dlhé. Vtedy sú aj všetky uhly rôzne veľké. Rovnoramenný trojuholník má dve strany rovnako dlhé (voláme ich ramená) a tretiu stranu nazývame základňa. Uhly pri základni sú vždy rovnaké!
Rovnostranný trojuholník je najšpeciálnejší - všetky tri strany sú rovnako dlhé a všetky tri uhly majú presne 60°. Je to akási "dokonalá" verzia trojuholníka.
Zaujímavosť: Rovnostranný trojuholník je vlastne aj rovnoramenný, pretože má aspoň dve strany rovnaké!
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Triedenie trojuholníkov podľa uhlov
Teraz sa pozrieme na trojuholníky z pohľadu ich uhlov. Toto rozdelenie je super dôležité pre riešenie úloh!
Ostrouhlý trojuholník má všetky tri uhly ostré (menšie ako 90°). Pravouhlý trojuholník má jeden uhol presne 90° - strany pri tomto uhle nazývame odvesny a najdlhšiu stranu oproti pravému uhlu nazývame prepona.
Tupouhlý trojuholník má jeden uhol tupý (väčší ako 90°). Pamätaj si dôležité pravidlo: trojuholník nemôže mať dva pravé alebo dva tupé uhly - vždy len jeden!
Praktický tip: Pravé uhly nájdeš všade okolo seba - rohy stola, rohý knihy alebo rohý telefónu majú všetky 90°.
Sign up to see the contentIt's free!
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Join milions of students
Súčet uhlov v trojuholníku - najdôležitejšie pravidlo
Tu prichádza na rad najdôležitejšie pravidlo o trojuholníkoch, ktoré si musíš zapamätať na celý život!
Súčet všetkých vnútorných uhlov v každom trojuholníku je vždy 180°. To znamená α + β + γ = 180°. Toto pravidlo platí úplně pre každý trojuholník - či už je malý alebo veľký, rovnostranný alebo rôznostranný.
Toto pravidlo ti pomôže vypočítať chýbajúci uhol, ak poznáš dva ostatné. Jednoducho odčítaš známe uhly od 180° a máš výsledok! Skvelý trik na kontrolu: vždy si spočítaj všetky tri uhly - ak ti nevyjde 180°, niekde je chyba.
Predstav si to takto: Keby si vystrihol trojuholník a odtrhol jeho rohy, potom ich priložil k sebe, vytvorili by rovnú čiaru - a to je presne 180°!
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Príklady a riešenie úloh
Teraz si ukážeme, ako používať to, čo sme sa naučili, na konkrétnych príkladoch. Takto to bude na testoch!
Príklad s triedením podľa strán: Trojuholník so stranami 6 cm, 6 cm, 8 cm je rovnoramenný, pretože dve strany (6 cm) sú rovnaké. Príklad s triedením podľa uhlov: Trojuholník s uhlami 45°, 45°, 90° je pravouhlý, pretože má jeden uhol presne 90°.
Výpočet chýbajúceho uhla: Ak máš uhly α = 65° a β = 40°, chýbajúci uhol γ vypočítaš takto: γ = 180° - 65° - 40° = 75°. Vždy si skontroluj: 65° + 40° + 75° = 180° ✓
Skúšobný tip: Na testoch vždy kontroluj súčet uhlov - je to najrýchlejší způsob, ako zistiť, či máš správny výsledok!
Sign up to see the contentIt's free!
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Dôležité tipy a triky na zapamätanie
Jeden trojuholník môže patriť do viacerých skupín súčasne. Napríklad rovnostranný trojuholník je zároveň aj rovnoramenný a ostrouhlý!
Pri riešení úloh vždy používaj správne jednotky - uhly v stupňoch (°), strany v centimetroch (cm). Pomôcky ako pravítko a uhlomer ti pomôžu lepšie si predstaviť, o aký trojuholník ide.
Pamätaj si označenia: malé písmená pre strany, veľké písmená pre vrcholy, grécke písmená pre uhly. Toto ti ušetrí veľa času pri riešení úloh!
Záverečná rada: Cvič na rôznych príkladoch - čím viac úloh vyriešiš, tým istejší budeš v rozoznávaní a počítaní s trojuholníkmi!
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 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.
Where can I download the Knowunity app?
You can download the app from Google Play Store and 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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4.6/5
App Store
4.7/5
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 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 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 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 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