STEP 1 - WRAP RIBBON: Take the ribbon and wrap it around a glass. Mark where the ribbon overlaps itself. Image caption, STEP 2 - CUT CIRCUMFERENCE: Cut the ribbon at the point where it overlaps.

Around 250 B.C., the Greek mathematician Archimedes calculated the ratio of a circle's circumference to its diameter ... gives a value of 4 (8/9) 2, or 3.1605. Archimedes' value, however, was ...

If you remember from school, Pi is the ratio of a circle's circumference to its diameter. It is a number that is usually written as 3.14. Around Pi Day, or March 14, you know 3-1-4. We have shown ...