right-angled triangle
1
2.8
- noun
- /ˈraɪtˌæŋɡəld ˈtraɪæŋɡəl/
- UK
:
triángulo rectángulo
- To find the area of a right-angled triangle, you multiply the lengths of the two legs and divide by two.
Examples
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In a right-angled triangle, the two sides that make the right angle are called the legs.
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Likewise, triangles were classified generally as acute-angled triangles, right-angled triangles, and obtuse-angled triangles.
Blog text (29) -
In any right-angled triangle, the square on the side subtending the right angle, is equal to... what?
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In any right-angled triangle...
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To right-angled triangles.
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Here's an objection to the Pythagorean Theorem: there is a right-angled triangle of sides 3, 4, and 5, but 32 + 42 = 26 and 52 = 25.
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The longest side of a right-angled triangle, opposite the right angle, is known as the hypotenuse.
Synonyms
2
3.2
A triangle with one angle equal to 90 degrees
Antonyms
Surface Forms
Morphology
right-angled + triangle
The meaning is directly and transparently derived from its parts: 'right-angled' signals the presence of a right (90°) angle and 'triangle' names a three-sided figure, so the compound straightforwardly means a triangle with a 90° angle. This compositional pattern is standard and cross-linguistically common, so a B1 learner who knows the constituent words will readily infer the intended meaning.
Etymology
Right-angled triangle comes from geometry: a right angle is a perfect 90-degree corner. The word right here once meant 'straight' or 'correct', so a right-angled triangle is simply a triangle with one 'right' corner of 90 degrees.