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triangle

triangle

58 1.0
A flat shape with three straight sides and three angles
  • noun
  • /ˈtraɪæŋɡəl/
translation icon : triángulo
  • The flag was designed in the shape of a triangle, symbolizing progress and unity.
  • equilateral triangle
  • isosceles triangle
  • right triangle

And at the top of the triangle is narcissism.

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Examples

  • Think of the vertical side of the dashed triangle as its base, of length 6.

    Academic text (2001)
  • What can we say about this small triangle and this large triangle?

  • However, we do see that this is a triangle, a right triangle.

  • Both feet must remain in the triangle at all times.

  • CAB is a right angle triangle.

  • Find the area of the triangle drawn on the dot paper in Figure 5.

    Academic text (2001)
  • Notice that the three shaded triangles are all right triangles, which makes their area easy to determine.

    Academic text (2001)
  • We can use this formula because all triangles in our Cartesian coordinate system are right triangles.

    Academic text (2011)
  • The artist painted a vibrant triangle to represent the harmony between earth, water, and sky.

  • In geometry class, we learned that the sum of the angles in a triangle is always 180 degrees.

Synonyms

polygon
vstriangle
  • Specialized
7 3.9

A flat closed shape with at least three straight sides and angles, like a triangle or square

means only the three-sided case and excludes shapes with more sides
trilateral
vstriangle
6.3

A shape with three straight sides and three angles

applies also to any flat object or thing shaped like that
trigon
vstriangle
  • Archaic
9.4

A flat shape with three sides

is the common modern term for any such three-sided flat shape

Compounds

An area of sea between Miami, Bermuda, and Puerto Rico where ships and planes are said to disappear

right triangle
  • Specialized
2 3.2

A triangle with one angle equal to 90 degrees

isosceles triangle
  • Specialized
1 3.4

A triangle with two sides of the same length

Bermuda Triangle
  • Informal
1 5.8

A part of a project where tasks, decisions, or resources disappear and never get done

A triangle with one angle of 90 degrees

A triangle with all three sides the same length

obtuse triangle
  • Specialized
1 3.3

A triangle with one angle larger than 90 degrees

oblique triangle
  • Specialized
1 6.9

A triangle with no right angle

Pythagorean triangle
  • Specialized
1 6.1

Triangle with a right angle whose sides are whole numbers and follow a^2 + b^2 = c^2

scalene triangle
  • Specialized
1 4.4

A triangle that has all sides of different lengths and all angles of different sizes

equiangular triangle
  • Specialized
5.8

A triangle with three equal angles, each 60 degrees

acute-angled triangle
  • Specialized
3.2

A triangle in which all three angles are less than 90 degrees

acute triangle
  • Specialized
3.9

A triangle with all three angles less than 90 degrees

A romantic relationship between three people with love and jealousy

4.7

A triangle with one angle greater than 90 degrees

A small group of three bright stars in the southern sky near Circinus and Apus

spherical triangle
  • Specialized
9.8

A triangle on a sphere made by three arcs of great circles

How Many Sides

dodecagon
  • Specialized
1 8.2
decagon
  • Specialized
6.7
nonagon
  • Specialized
7.6
octagon
7 3.3
hexagon
5 2.8
pentagon
1 3.0
triangle
58 1.0

Surface Forms

triangle singular
triangles plural

Morphology

triangle = angle (transparent) = tri + angle

The meaning 'three-angled figure' follows directly from the combining form 'tri-' and the noun 'angle'.

Etymology

Triangle comes from the parts tri- meaning 'three' and angle meaning 'corner', so a triangle is simply a flat shape with 'three' corners and three sides.