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What is an equilateral triangle?
In GCSE Maths, an equilateral triangle is a special type of triangle in which all three sides have the same (equal) length. Each of the three internal angles in an equilateral triangle is equal to 60°.
Other properties of an equilateral triangle include having three lines of symmetry (from each corner to the middle of the opposite side) and having rotational symmetry of order 3 (rotating it by 120° gives the same triangle). An equilateral triangle is a special type of isosceles triangle, but cannot be a scalene triangle, nor a right-angled triangle.
Equilateral triangle revision resources to ace your exams
Equilateral triangles are covered in our revision notes on 2D shapes and basic angle properties from GCSE Maths. You can also have a go at our related exam questions and flashcards to test your understanding. Don’t forget to check out the past papers for more general exam revision.
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Written by Mark Curtis
Maths9 articlesMark graduated twice from the University of Oxford: once in 2009 with a First in Mathematics, then again in 2013 with a PhD (DPhil) in Mathematics. He has had nine successful years as a secondary school teacher, specialising in A-Level Further Maths and running extension classes for Oxbridge Maths applicants. Alongside his teaching, he has written five internal textbooks, introduced new spiralling school curriculums and trained other Maths teachers through outreach programmes.
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