Hawkins’ fifth crop-circle theorem involves a triangle and various concentric circles touching the triangle’s sides and corners. Different triangles give different sets of circles.

Named for Plato, who theorized that the classical elements were made of these regular polyhedrons, three of the Platonic solids are composed of equilateral triangles: the tetrahedron, octahedron ...

A pretty theorem in the latter is that all equilateral triangles in a given plane project upon another plane into triangles having the same Brocard angle.

Learn about and revise angles, lines and multi-sided shapes and their properties with this BBC Bitesize GCSE Maths Eduqas study guide.

Pascal’s triangle is a never-ending equilateral triangle of numbers that follow a rule of adding the two numbers above to get the number below. Two of the sides are “all 1's” and because the ...

If you start with an equilateral triangle, you’ll find that you can rotate it by multiples of 120 degrees without changing how it looks. If you start with a circle, you can rotate it by any angle.

Learn about and revise angles, lines and multi-sided shapes and their properties with GCSE Bitesize AQA Maths.