Meaning & use
right angle
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Meaning
nouncountablemathematics
An angle of exactly 90 degrees, formed when two lines meet perpendicularly.
Grammar: Countable: use 'a right angle' or 'right angles.'
Patterns
- a right angle
- at a right angle
- at right angles to something
The corner of a square forms a right angle.
Draw a line at a right angle to the base.
The two walls meet at right angles.
Word forms
| plural | right angles |
|---|
Common combinations
- at a right angle
- The pole stands at a right angle to the ground.
- form a right angle
- The two beams form a right angle where they cross.
- a right angle to something
- Cut the paper at a right angle to the edge.
- right angle triangle
- A right angle triangle has one 90-degree corner.
Synonyms and how they differ
- square angle
- A less common term for a 90-degree angle; 'right angle' is the standard term in math.
Word family
- right-angled adjective
- Having a right angle or right angles, as in a right-angled triangle.
Commonly confused: right angle or straight angle? right angle or acute angle?
right angle vs straight angle
A straight angle is 180 degrees, forming a straight line, not 90 degrees.
right angle vs acute angle
An acute angle is less than 90 degrees, while a right angle is exactly 90 degrees.
Practice
A right angle measures exactly how many degrees?
Choose one answer.
A right angle is exactly 90 degrees. 45 degrees is an acute angle, 180 degrees is a straight angle, and 360 degrees is a full turn.
Make it your own
Write a sentence using “right angle”, then check it and compare it with the examples above.