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 ...

All circle calculations use the constant π (pi). The circumference close circumference The distance around a circle; its perimeter. divided by the diameter close diameter The distance across the ...

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.