The circumference of a circle is the distance around the shape. The ability to round a number to a number of decimal places or to a number of significant figures means that answers can be written to ...

Pi, a mathematical constant denoted by the Greek letter π, is the ratio of a circle's circumference C to its diameter d: π = C/d. The circumference of a circle is, in turn, equal to 2πr, where r is ...

Beth Py-Lieberman - Author, The Object at Hand: Intriguing and Inspiring Stories from the Smithsonian Collections Every year, the celebration of Pi Day (March 14 is 3.14) grows more ambitious. Math ...

The radius of a circle or a sphere is the distance between the center and the edge. The radius can be used to calculate a circle's diameter, area and circumference. Likewise, a sphere's volume is ...

June 28. National Paul Bunyan Day, National Insurance Awareness Day, National … Tau Day? Today (June 28) is the unofficial holiday Tau Day, meant to celebrate the number tau, that works out to ...