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 ...

March 14, 2018, is Pi Day — that’s pi, not pie — and on Wednesday, Google marks the 30th anniversary of the math-inspired holiday with a special Doodle. Pi, denoted by the Greek letter “π”, has been ...