right triangle: meaning, definition, pronunciation and examples
Mid-lowAcademic, Technical, Educational
Quick answer
What does “right triangle” mean?
A triangle containing one 90-degree (right) angle.
Audio
Pronunciation
Definition
Meaning and Definition
A triangle containing one 90-degree (right) angle.
The fundamental geometric shape defined by the Pythagorean theorem (a² + b² = c²), where the side opposite the right angle (the hypotenuse) is the longest side.
Dialectal Variation
British vs American Usage
Differences
The term 'right-angled triangle' is slightly more common in UK English, while 'right triangle' is dominant in US English. Both are understood everywhere.
Connotations
None. The terms are mathematically equivalent and carry no stylistic connotations.
Frequency
In UK educational contexts (e.g., GCSE), 'right-angled triangle' is the standard textbook term. US textbooks and standardized tests (e.g., SAT) exclusively use 'right triangle'.
Grammar
How to Use “right triangle” in a Sentence
[subject] is a right triangle[verb] the properties of a right trianglecalculate [object] using a right triangleVocabulary
Collocations
Examples
Examples of “right triangle” in a Sentence
adjective
British English
- The right-triangle geometry problem was challenging.
- We used a right-triangle calculation.
American English
- The right-triangle theorem is fundamental.
- It's a simple right-triangle trigonometry exercise.
Usage
Meaning in Context
Business
Rare, except in technical fields like engineering, construction, or design.
Academic
Standard in mathematics, geometry, physics, and engineering curricula.
Everyday
Used in practical contexts like DIY, carpentry, or when explaining basic geometry.
Technical
The precise term in geometry, trigonometry, surveying, and technical drawing.
Vocabulary
Synonyms of “right triangle”
Strong
Neutral
Vocabulary
Antonyms of “right triangle”
Watch out
Common Mistakes When Using “right triangle”
- Misspelling as 'right angel triangle'.
- Confusing the hypotenuse with one of the legs (the sides forming the right angle).
- Using the Pythagorean theorem on non-right triangles.
FAQ
Frequently Asked Questions
No. A right triangle can be isosceles (if its two legs are equal, creating 45-45-90 angles) or scalene (with all sides and angles different, like a 30-60-90 triangle).
There is no mathematical difference; they are synonyms. 'Right triangle' is standard in American English, while 'right-angled triangle' is slightly more common in British English.
No. A triangle can only have one angle that is 90° or greater. Since a right triangle has one 90° angle, the other two angles must be acute (less than 90°), summing to 90°.
It provides an exact mathematical relationship between the lengths of all three sides, allowing you to calculate any missing side if you know the other two, which is fundamental to geometry, trigonometry, and many practical applications.
A triangle containing one 90-degree (right) angle.
Right triangle is usually academic, technical, educational in register.
Right triangle: in British English it is pronounced /ˈraɪt ˌtraɪ.æŋ.ɡl̩/, and in American English it is pronounced /ˈraɪt ˌtraɪ.æŋ.ɡl̩/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think of the corner of a book or a sheet of paper – it forms a 'right' (correct/90-degree) angle, creating a 'right triangle' if you draw a line across.
Conceptual Metaphor
A FOUNDATION (for trigonometry), a TOOL (for calculation), a BUILDING BLOCK (of geometry).
Practice
Quiz
Which of the following is TRUE for every right triangle?