Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
triangle
Table of Contents
Introduction References & Edit History Related Topics
Images
Standard lettering of a triangle Area of a triangle Pythagorean theorem Three theorems of congruent triangles Figure 6: Construction for similar triangles (see text). Contrasting triangles in Euclidean, elliptic, and hyperbolic spaces. Fundamental theorem of similarity Chinese and Greek geometric theorems triangle inscribed in a circle Figure 9: If the angles of triangle ABC (representing any triangle) are trisected, then triangle DEF is equilateral.
Discover
Happy, smiling, flying pig
7 Everyday English Idioms and Where They Come From
Drinking water is poured into a glass.
Water Fluoridation: Just the Facts
Figure 13: A Maxim machine gun, belt-fed and water-cooled, operated by German infantrymen, World War I.
7 Deadliest Weapons in History
Ethel Rosenberg arrested in August 1950. Photograph dated Aug. 8, 1950. American civilians executed for espionage. Spies, communists, Julius Rosenberg
Spies Like Us: 10 Famous Names in the Espionage Game
Aspirin pills.
7 Drugs that Changed the World
Portrait of a mountain gorilla at a short distance. gorilla close up portrait.The mountain gorilla (Gorilla beringei beringei)
Falling Stars: 10 of the Most Famous Endangered Species
Internet http://www blue screen. Hompepage blog 2009, history and society, media news television, crowd opinion protest, In the News 2009, breaking news
Who Invented the Internet?

triangle: Related Content

verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Share
Share to social media
URL
https://www.britannica.com/facts/triangle-mathematics
Written and fact-checked by
The Information Architects of Encyclopaedia Britannica

The Information Architects maintain a master list of the topics included in the corpus of  Encyclopædia Britannica, and create and manage the relationships between them.
The Information Architects of Encyclopaedia Britannica

Photos

Standard lettering of a triangle
Area of a triangle
Pythagorean theorem
Three theorems of congruent triangles
Figure 6: Construction for similar triangles (see text).
Contrasting triangles in Euclidean, elliptic, and hyperbolic spaces.
Fundamental theorem of similarity
Chinese and Greek geometric theorems
triangle inscribed in a circle
Figure 9: If the angles of triangle ABC (representing any triangle) are trisected, then triangle DEF is equilateral.
See All Images →

Related Topics and References

Topics

Key People

Heron of Alexandria
Greek mathematician