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equilateral triangle

equilateral triangle

1 3.2
A triangle with all three sides the same length
  • noun
  • /ˌiːkwɪˈlætərəl ˈtraɪæŋɡəl/
translation icon : triángulo equilátero
  • Creating a triangle using the above methods will always result in an equilateral triangle (with all sides of equal length and all three angles at 60 degrees).
  • form an equilateral triangle

Examples

  • Between the yellow man and the black woman, meanwhile, the scenes of the second act (with one, two, and three dancers, respectively) together form an equilateral triangle, a visual triad symbolizing the ballet's overall schema.

    Academic text (2003)
  • The interior angle of an equilateral triangle measures 60 degrees.

  • An equilateral triangle has three equal sides.

    Academic text (2009)
  • Students arrive in the classroom and find an equilateral triangle drawn on the board.

    Academic text (2004)
  • Such standardized data can be plotted on an equilateral triangle (Fig. 2).

    Academic text (1994)
  • An equilateral triangle has three sides that are all the same length.

  • Students discovered an equilateral triangle sketched on the classroom whiteboard.

Synonyms

delta
vsequilateral triangle
1 5.1

A triangular shape with all sides the same length

is the abstract mathematical figure rather than a shaped object
equiangular triangle
vsequilateral triangle
  • Specialized
5.8

A triangle with three equal angles, each 60 degrees

adds equal side lengths as a required property

How Equal

equilateral triangle
1 3.2
isosceles triangle
  • Specialized
1 3.4
scalene triangle
  • Specialized
1 4.4

Surface Forms

Morphology

equilateral + triangle

The phrase is directly compositional: 'equilateral' specifies 'equal sides' and 'triangle' is a three-sided figure, so a learner who knows both words can infer a triangle with all sides equal (and thus equal angles). This pattern is cross-linguistically common in geometric terminology and follows standard adjective+noun composition, making it immediately understandable to a B1 learner.

Etymology

Equilateral triangle comes from a simple, literal idea: equilateral means 'equal sides', so an triangle with all three sides the same length has all angles equal.