Pi | Definition, Symbol, Number, & Facts (2024)

FAQs

Pi | Definition, Symbol, Number, & Facts? ›

Pi Day

The value of pi is approximately 3.14, or 22/7. To 39 decimal places, pi is 3.141592653589793238462643383279502884197. Pi is an irrational number, which means it is not equal to the ratio of any two whole numbers.

Deceptively simple, Pi is the ratio of the circumference of a circle to its diameter, calculated by dividing the length of the diameter of a circle into its circumference. The miraculous fact about Pi is that no matter the size of the circle, the value does not change, making Pi a mathematical constant.

It is also called Archimedes' constant which was named after the Greek mathematician, Archimedes, who created an algorithm to approximate the pi value. The value of pi is irrational, which means that the count of digits after the decimal point is infinite. It is used as either 3.1415929 or 22/7.

Because π is irrational, it has an infinite number of digits in its decimal representation, and does not settle into an infinitely repeating pattern of digits. There are several proofs that π is irrational; they generally require calculus and rely on the reductio ad absurdum technique.

Pi shows that knowing, wholly, is an impossibility. The more we know, the more apparent it is that there is much more to know. For each individual, and for humanity as a whole, there is always that added bit that simply can't be figured out, no matter how much information or education we possess.

Engineers use pi to calculate the stress and strain on materials, design bridges and buildings, and develop new technologies. Physicists use pi in calculations related to waves, such as sound and light waves, and to calculate the speed and momentum of particles.

Pi is an irrational number Pi is an irrational number, which means that it cannot be expressed as a finite decimal or fraction. Its decimal representation goes on forever, without repeating. This property has intrigued mathematicians for centuries, and many have attempted to calculate pi to as many digits as possible.

pi = 3.1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679 8214808651 3282306647 0938446095 5058223172 5359408128 4811174502 8410270193 8521105559 6446229489 5493038196 4428810975 6659334461 2847564823 3786783165 2712019091 4564856692 3460348610 4543266482 ...

Will pi eventually repeat? ›

Pi never repeats itself. It is also infinite, and contains every single possible combination of numbers.

Rhyme to memorize.

This mnemonic relies on using the rhythm and pattern to recall the memorized numbers. Lots of other memorization songs use the same technique: "If numbers had a heaven / their God would surely be / 3.14159 / 26535." Try writing your own song or rhyme to help yourself remember.

The first recorded use of π as a mathematical symbol comes from the Welsh mathematician William Jones in a 1706 work called Synopsis Palmariorum Matheseos, in which he abbreviated the Greek περιϕέρεια, (meaning “circumference,” or “periphery”) to its first letter: π.

Introduced by William Jones in 1706, use of the symbol was popularized by Leonhard Euler, who adopted it in 1737. An eighteenth-century French mathematician named Georges Buffon devised a way to calculate π based on probability.

The value of Pi (π) is the ratio of the circumference of a circle to its diameter and is approximately equal to 3.14159. In a circle, if you divide the circumference (is the total distance around the circle) by the diameter, you will get exactly the same number.

The concept of pi is ancient — it's been known to humanity for at least four thousand years. In 2000 BCE, Babylonian mathematicians performed the first known calculation of the area of a circle using the circumference of an inscribed hexagon, and derived an approximate value for pi of 3.125.

The first five digits of this iconic number are, 3.1415…which happens to be the date Saturday, and thus, the celebrations. In honor of the mathematical wonder, we spoke to Aatish Bhatia, an engineer at Princeton University and the author of the Empirical Zeal blog, to help answer some of your most basic Pi questions.

Why is it called Pi? It wasn't given its name until 1706, when Welsh mathematician William Jones began using the Greek symbol for the number. Why that letter? It's the first Greek letter in the words “periphery” and “perimeter,” and pi is the ratio of a circle's periphery — or circumference — to its diameter.

Pi to 5 decimals is 3.14159. Divided by 4 (producing the necessary sum of the infinite series), that's . 7853975.