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 ...

Today's Google doodle celebrates the 30th anniversary of Pi day. Pi day, observed on the 14th of March every year, celebrates the mathematical constant Pi. Pi represents the ratio of a circumference ...

Pi is denoted by the Greek letter π. It is a mathematical constant and is approximately equal to 3.14159. It is defined as the ratio of a circle's circumference to its diameter. It was first ...

The mathematical constant pi is under threat from a group of detractors who will be marking "Tau Day" on Tuesday. Tau Day revellers suggest a constant called tau should take its place: twice as large ...