What is an example of constant used in math?

An example of a constant used in math is the number pi (π), which represents the ratio of a circle's circumference to its diameter. Pi is approximately equal to 3.14159 and is an irrational number, meaning it has an infinite number of non-repeating decimal places. It is widely used in geometry, trigonometry, and calculus. Another common constant is Euler's number (e), approximately equal to 2.71828, which is essential in exponential growth calculations and natural logarithms.