How do you use the word "triangle" in a sentence?

Here are real-life examples of using "triangle": The sum of all the angles in a triangle equals 180 degrees. It is hard to define "triangle."

Triangle Meaning

/ˈtɹaɪəŋɡəl/

Definition, CEFR level A1, pronunciation, examples, and quiz.

Definition

nounA polygon with three sides and three angles.

nounA set square.

Sentence Examples

The sum of all the angles in a triangle equals 180 degrees.

It is hard to define "triangle."

If a figure has three sides, it is a triangle.

CEFR Practice Quiz

The artist drew a perfect ____ with three equal sides and angles using a ruler.

CEFR Practice Quiz (Alternate)

The student used a ruler to draw a perfect ____ with three equal sides in her geometry notebook this morning today.

Word Origin & History

PIE word *tréyes From Middle English triangle, from Old French triangle, from Latin triangulum, noun use of adjective triangulus (“three-cornered, having three angles”), from trēs (“three”) + angulus (“corner, angle”), equivalent to tri- + -angle.

Literary Quotations & Historical Citations

"The wedge-shaped character was the triangle, the archaic Paleolithic sign of the vulva; the pubic triangle was at the end of the phallic stylus." — 1981, William Irwin Thompson, The Time Falling Bodies Take to Light: Mythology, Sexuality and the Origins of Culture, London: Rider/Hutchinson & Co., page 22:

"I was flogged in 1840. To this day I feel a pain in the chest from the triangles." — 1851, Henry Mayhew, London Labour and the London Poor, published 1861:

"But nothing is said as to what we are to do with the negro when we have cut him off from absolute dominion; we are not informed if we may spread him on the triangles as aforetime;" — 1868, “The Week”, in The Nation, volume 6, number 149:

"After turning on the triangle at Jeumont, we set off light engine back to Aulnoye." — 1961 March, ""Balmore"", “Driving and firing modern French steam locomotives”, in Trains Illustrated, page 147:

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