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Mathematics vocabulary · Geometry

Right angle

Meaning in mathematics, with examples

nounCore term

In mathematics, right angle means: An angle of exactly 90 degrees, like the corner of a square, usually marked on diagrams with a small square.

In Turkish: dik açı

How it is used

Lines that meet at a right angle are perpendicular. Common phrases are 'at right angles to', 'a right-angled triangle' (UK) and 'a right triangle' (US). Two right angles make a straight angle of 180°.

Example sentences

  1. The wall meets the floor at a right angle.

  2. Mark the right angle on the diagram before you use Pythagoras.

Common collocations

  • at a right angle
  • at right angles to
  • right-angled triangle
  • mark the right angle
  • angleThe amount of turn between two lines or rays that meet at a point, measured in degrees or radians.
  • hypotenuseThe longest side of a right triangle, which is the side opposite the right angle.
  • Pythagorean theoremThe rule that in a right triangle the square of the hypotenuse equals the sum of the squares of the other two sides: a² + b² = c².
  • triangleA flat shape with three straight sides and three angles; the angles inside any triangle always add up to 180 degrees.
  • parallelAlways the same distance apart and never meeting, however far they are extended; used of lines, planes and the sides of shapes.

More terms: Geometry

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