What is pi? 1.2 2007/05/21 12:00:59 GMT-5 2007/08/16 13:11:38.937 GMT-5 Christopher D. Schmitz cdschmit@uiuc.edu Christopher D. Schmitz cdschmit@uiuc.edu π pi This module presents a brief introduction to the commonly-assigned value of pi (approximately 3.1415). The mathematical constant represented by the Greek letter π should be considered nothing more than the "cheat factor" needed to convert an easily-measured parameter of a circle, namely its radius, to a not-so-easily-measured parameter, its area. The well-known formula is given by A=πr2. The value of π is just a bit over 3, but it is more accurately 3.1...or 3.14...or 3.141...or 3.1415. Acually, it requires a never-ending number of values past the decimal point to exactly represent this nasty little number. No wonder we use the symbol π rather than trying to write it out every time we reference it. This way, we can just let our calculator remember the actual value (to a very high precision) whenever we need it. Because so many things in life can be described by "motion along a circle," the value π appears very often in science and engineering.