Question: What is Pi ?


When the length of the circumference of a circle is divided by the length of its diameter, the result is always the same number. This number is slightly more than 3.

Pi is an irrational number, which means that it cannot be expressed as a fraction m/n, where m and n are integers. Consequently its decimal representation never ends or repeats. Beyond being irrational, it is a transcendental number.

An electronic calculator gives π as 3.1415927. This is not exact, but accurate enough for most practical purposes. Pi is an irrational number so it cannot be expressed exactly as a friction. 22/7 is often used as a approximation to π, but 355/113 proposed by the ancient Chinese astronomer Ch’ung- Chi much better. π occurs in all the formulas for measuring the areas and volumes of circular objects such as the circle, sphere, cylinder and cone.