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# What is pi?

Module by: Christopher Schmitz. E-mail the author

Summary: 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 = π r2. 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.

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