### 5 GREAT IRRATIONAL NUMBERS

- •πPi - The ratio of a circle's circumference to its diameter. 3.14159...
- •eEuler's Number - The base at which a population's exponential growth rate equals its size. 2.71828...
- •ψThe Golden Ratio - the proportion by which a square can be cut from a rectangle, leaving behind a rectangle of the same proportion. Also the limit of the ratios of the Fibonacci numbers. 1.61803...
- •√2The length of the diagonal of a unit square. The first number proven to be irrational. 1.41421...
- •γEuler Mascheroni Constant - the difference between the sum of the first n terms of the harmonic series and the natural logarithm for large n. Closely related to the distribution of prime numbers. 0.57721...