triangle

//ˈtraɪæŋɡəl//

Nouns
A2

Translation

triangle

Definition

A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry and is defined by three straight line segments that connect three non-collinear points. Triangles are classified by their side lengths (equilateral, isosceles, scalene) or by their angles (acute, right, obtuse). This shape is fundamental in mathematics, engineering, and design, often used to calculate area, angles, and structural stability. In everyday language, 'triangle' can also refer to a triangular object or a musical percussion instrument made of metal bent into a triangle shape.

Example

  • She drew a triangle on the whiteboard to explain the geometry problem.

  • The roof of the house is shaped like a triangle, which helps rainwater run off easily.

  • In the game, players must arrange the balls into a triangle at the start of each round.

  • The musician struck the triangle with a metal rod, producing a clear, ringing sound.

  • A right triangle has one angle that measures exactly 90 degrees.

  • The hiker followed a triangle-shaped path around the mountain to return to the starting point.

  • The company logo features a blue triangle inside a circle.

  • To calculate the area of a triangle, multiply the base by the height and then divide by two.

  • The warning sign on the road is a yellow triangle with an exclamation mark.

  • In the art class, students used triangles and squares to create a geometric pattern.

Synonyms

trigon
three-sided polygon
delta shape

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