Though this ancient empire usually used 3 as an estimate, at least one tablet (1900-1680 BC) gives a value of 3.125

Problem 48 estimates the value by comparing a circle, approximated by an octagon, and its circumscribed square; 1650 BC; each side of the circumscibing square is trisected

and the corner triangles are then removed; the resulting octagonal figure approximates the circle

And he made a molten sea, ten cubits from the one brim to the other: it was round all about, and his height was five cubits: and a line of thirty cubits did compass it round about

Using the Pythagorean Theorem to find the areas of two regular 96-polygons: the polygon inscribed within the circle and the polygon within which the circle was inscribed, he

established the lower and upper bounds of π; 3.1408... < π < 3.1428...

Late first, early second century; used square root of 10 to estimate π ≈ 3.16

In Nine Chapters, used π ≈ 3 as an estimate; used 3072-gon to obtain π ≈ 3.14159...; had previously used one inscribed 96-gon

Starting with an inscribed regular 24,576-gon and performing lengthy calculations involving hundreds of square roots carried out to 9 decimal places, calculated π ≈ 355/113;

π ≈ 3.1415929…

AD 500; speculated that he used the word āsanna (approaching), to mean that his estimate, π ≈ 62832/20000, π ≈ 3.1416, was not only an approximation but that the value is

incommensurate

First KNOWN to determine, though he did not prove, that π is irrational; “The ratio [π] cannot be known…it is impossible to arrive at a perfectly accurate ratio”

Used an infinite sum to estimate pi: π/4 ≈ 1 - 1/3 + 1/5 - 1/7 + 1/9 - ...

Though, this elegant formula is one of the simplest ever discovered to calculate pi, it is also fairly useless; 300 terms of the series are required to get only 2 decimal places, and 10,000 terms are required for 4 decimal places; to compute 100 digits, you would have to calculate more terms than there are particles in the universe; however, this formula set the stage for a handful of other formulas that would be more effective.

Introduced π as the symbol for the ratio of the circumference of a circle to its radius in Synopsis Palmariorum Mathseos; probably inspired by the greek word for circumference:

perijeria (peripheria)

Popularized π as the symbol for the ratio of the circumference of a circle to its ratio

1761; First proof that π was irrational

Used the earliest problem in geometric probability to determine the value of π; 'Suppose we have a floor made of parallel strips of wood, each the same width, and we

drop a needle onto the floor. What is the probability that the needle will lie across a line between two strips?'; π is calculated to be 4 times this amount

1794; Proved that π^2 was irrational

1882; Proved that π was transcendental, and therefore is not the root of any integer polynomials; consequently the famous and old problem of squaring the circle with a ruler and a

compass is insoluble

1897; Based on a claim that he had been taught the value of π, the Indiana State Assembly passed unanimously, 67-0, a law decreeing π = 3.2 (Senate refused to pass the bill)

1877-1938; Jewish Scholar who defined π in terms of cos; though a brilliant insight, it was used as a pretext for his firing from the University of Gottingen during the early Nazi

years

Composed, recorded and put on YouTube a musical interpretation of π; decided the song would be in C, assigned each note a number: C=1, D=2 and so on up through 9;

played the sequence of pi: 3.14159 through 31 decimal places; assigned numbers to chords, but could only play the chords every other note and still make it sound vaguely musical; used pi as the basis for the tempo,157 beats per minute, which is half of 314; played this on several instruments, layered them to make a song; result isn't exactly catchy, but it's certainly melodic

Artist who won a design contest for the Downsview subway station in Toronto, basing her design on π; tile pattern with first color 3 tiles wide, the second color 1 tile wide, the

third four tiles wide, and so foth

The writer/director of the 1998 American surrealist psychological thriller, π, in which a mathematician seeking a pattern to the recurring digits of π is chased by the DOD,

which wants his research to help predict the stock market, and Hasidic Jews who want his help in finding the lost name of God

Person who foils an evil computer by commanding it to calculate the last digit of π

Comedian who quipped: “What do you get if you divide the circumference of a jack-o'-lantern by its diameter? Pumpkin π.”

In this person's trial there were arguments between defense attorney Robert Blasier and an FBI agent about the actual value of pi, seemingly to reveal flaws in the FBI agent’s

intellectual acumen

The ratio of the vertical height of this object to the perimeter of its base is π

In 1995 he memorized 42,195 places of π and is considered the current π champion

In 2002, a Japanese scientist found 1.24 trillion digits of pi using this powerful computer

He was born on π day, 3/14/1879

Wrote 'Eternal God—for whom who ever dare Seek new expressions, do the circle square, And thrust into straight corners of poor wit Thee, who art cornerless and infinite—' on

the futility of calculating π

Number of decimal places of π which suffice for computing the circumference of a circle girding the known universe with an error no greater than the radius of a hydrogen atom

Number of decimal places of π which Sir Isaac Newton calculated

Number of times the sequence 123456 appears in the first million digits of π

Number of times the sequence 12345 appears in the first million digits of π

Number of times the sequence 012345 appears in the first million digits of π

The sum of the first 144 digits of π, proving there is something diabolical about the number