According to History Today, William Jones created pi in 1706. This mathematics teacher used the symbol to refer to the constant ratio of any circle's circumference to its diameter. More » Math Calculus

Pi Day is a nationally recognized date celebrating mathematics and the history of the mathematical term pi. Pi Day is observed and celebrated in many fun ways worldwide. More » Holidays & Celebrations Holidays

Some mathematical problems that feature pi are the area of a circle, a circle's circumference, arc length and the different surface area and volume formulas for a cone, sphere and cylinder. In mathematics, the ratio betw... More » Math Arithmetic
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Pi is not a rational number. It is considered irrational. A rational number is able to be written as a fraction with integers for both the numerator and denominator. More » Math Numbers

The number Pi, symbolized by a Greek letter, has a constant value that approximately equals 3.14159. Pi is an irrational number, which means it cannot be expressed as a common fraction, and it has an infinite decimal rep... More » Math Geometry

A math extrapolate formula is an equation used to predict the value of the dependent variable from an independent variable not found within the range of data. An example of such a formula is y=2x+5, when the range of val... More » Math Calculus

The cosine of 1 is 0.99 when evaluated in degrees and 0.54 when evaluated in radians. The value can be found by using the cosine function on a calculator or by evaluating the function manually. More » Math Calculus