Welcome to a city where pi equals 4 and circles aren’t round. By Steven Strogatz Photo illustrations by Jens Mortensen Each installment of “Math, Revealed” starts with an object, uncovers ...

In 1880, the German mathematician Ferdinand von Lindermann proved that pi is a transcendental number and that squaring a circle is impossible under the constraints of Euclidean geometry.

GCSE Edexcel Circles, sectors and arcs - Edexcel Circumference of a circle The circumference of a circle is its outside edge, and is the same distance from the centre at every point along its length.

Learn about and revise the different angle properties of circles described by different circle theorems with GCSE Bitesize Edexcel Maths.

5 Mathematical Formulas from Ancient Times Learn why the achievements of Egypt, Babylon and Greece, though child’s play today, still stand as remarkable feats of intellect.

Formula for Circumference of Circle Circumference = 2 × π × Radius ...

Using the formula C=2 pi r with fifteen decimal places of pi, you’d only be off on the true circumference of the circle by a centimeter or so. On solar scales, there’s no need to go further.

Today is Pi Day, but you should stop celebrating it and instead use tau as your circle constant. Tau Day — the true holiday — is celebrated on June 28th.

In "Once Upon a Prime," Sarah Hart takes readers on a fascinating tour of the world of numbers, finding connections between math and literature.

The question below is a geometry question from the ACT that students often have a hard time solving. It asks you to find the circumference of a circle.