Pi (pronounced "pie") is an irrational number with an approximate value of 3.14
Irrational numbers contain an infinite number of digits following the decimal point and cannot be expressed as a simple fraction of two integers. The square root of 2 is yet another famous example of an irrational number.
Commonly used in mathematics, Pi is symbolized by the Greek letter π and represents the ratio of a circle's circumference to its diameter. The circumference of a circle can be determined by multiplying π by the diameter (π×d), or by doubling π and multiplying by the radius (2×π×r). Thus, dividing the circumference of any given circle by its diameter should yield a result of approximately 3.14