Circumference pi, is represented by the Greek letter . The first few decimal digits of the numerical value of are 3.141592653589793 ... Pi is defined as the ratio of a circle's circumference to its diameter : Or, equivalently, as the ratio of the circumference to twice the radius. The above formula can be rearranged to solve for the circumference: The use of the mathematical constant is ubiquitous in mathematics, engineering, and science. In "Measurement of a Circle" written circa 250 BCE, Archimedes showed that this ratio (, since he did not use the name ) was greater than 3 but less
Outer Circle railway line Outer Circle railway line The Outer Circle was built in 1891 as a steam-era suburban railway line, in Melbourne, Australia. It covered much of the modern City of Boroondara, including the suburbs of (from north to south) Kew East, Camberwell, Burwood, Ashburton, and Malvern East. At its longest stage, it ran from Fairfield station, on what is today the Hurstbridge line, to Oakleigh station, on the current Pakenham and Cranbourne lines. The Outer Circle railway was first advocated by a group known as the Upper Yarra Railway League in 1867 who suggested that the Gippsland Railway could be brought into