Pi, a mathematical constant denoted by the Greek letter π, is the ratio of a circle's circumference C to its diameter d: π = C/d. The circumference of a circle is, in turn, equal to 2πr, where r is ...

Swiss researchers said on Monday they had calculated the mathematical constant pi to a new world-record level of exactitude. The constant π is represented in this mosaic outside the Mathematics ...

Imagine a cup of tea. Wrap a piece of string around the circumference of the cup, and measure the length of the string. Then, lay your spoon on top of the cup, making sure it lies across the center of ...