pi

2 ENTRIES FOUND:

pi

In mathematics, the ratio of the circumference of a circle to its diameter. An irrational number (see also transcendental number), it has an approximate value of 3.14, but its exact value must be represented by a symbol, the Greek letter . Pi is used in calculations involving lengths, areas, and volumes of circles, spheres, cylinders, and cones. It also arises frequently in problems dealing with certain periodic phenomena (e.g., motion of pendulums, alternating electric currents). By the end of the 20th century, computers had calculated pi to more than 200 billion decimal places.

This entry comes from Encyclopædia Britannica Concise.
For the full entry on pi, visit Britannica.com.

Seen & Heard

What made you look up pi? Please tell us what you were reading, watching or discussing that led you here.