I am Pi, the ratio of the circumference of a circle to its diameter. Picking up the phone here at the Smithsonian, I set out to find out more about Pi and how it is represented in the national ...

You have shown that the circumference of a circle is π × diameter. ... TIP: Try it with any circular object. Whatever the size, the circumference is always just over 3 × diameter.

To do this, start by cutting a 3-inch piece of string to serve as the radius of the circle. What’s the radius? It’s half the diameter. Okay, but what’s the diameter?

It is derived simply, by dividing the circumference of a circle by its diameter, or π = C/d, but the result is a never-ending "irrational" number: 3.14159265.

Yes, pi! The number with infinitely-repeating decimals that represents the ratio of the circumference of a circle to its diameter... and that also had every middle school know-it-all in a ...

Approximating Pi By Rick Groleau Posted 09.01.03 NOVA Around 250 B.C., the Greek mathematician Archimedes calculated the ratio of a circle's circumference to its diameter. A precise determination ...

It’s hard to pinpoint who, exactly, first became conscious of the constant ratio between the circumference of a circle and its diameter, though human civilizations seem to have been aware of it ...

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.

If I cut out circles of different diameters and measure the mass of the circle then I can calculate the area. If the area is also supposed to be π R2, I can make a plot of area vs. diameter squared.

This number, called π (or pi), is approximately 3.14. You have shown that the circumference of a circle is π × diameter.