Pi
0Loading crowd target
0Loading crowd target
8correct to beat the crowd
69 free Pi trivia questions with answers — science & nature quiz, new questions added Aug 2026.
64 free Pi trivia questions with answers. Dive into the world of mathematics' most iconic constant with our extensive Pi trivia quiz. Featuring 69 questions spanning from basic facts to advanced mathematical concepts, this quiz challenges both math enthusiasts and curious learners. Discover how much you really know about Pi (π) and its fascinating role in science and nature.
30 of 69 questions with answers and explanations. Play the quiz
Q 01A famous run of six consecutive 9s in the decimal expansion of π starts at roughly which decimal place?
The 762nd
The six consecutive 9s begin at the 762nd decimal place of π, a run nicknamed the Feynman point after Richard Feynman, who joked he wanted to memorize π that far and then say 'and so on'.
Q 02The Greek letter used to represent the mathematical constant was first introduced by which mathematician?
William Jones
Jones credited his equations to the 'ready pen of the truly ingenious Mr. John Machin', so Machin may have used the letter first; the notation was not widely adopted for decades.
Q 03Which mathematical property of pi means its decimal expansion is infinite and non-repeating?
Irrational
Pi is an irrational number, which means it cannot be expressed as a simple fraction and its decimal representation goes on forever without repeating.
Q 04Pi is transcendental: not the root of any non-zero polynomial with which type of coefficients?
Rational
Pi is not a root of any non-zero polynomial with rational coefficients, which is what transcendental means; every transcendental number is irrational, but not every irrational is transcendental, since √2 is a root of x² − 2.
Q 05Pi Day is celebrated annually on which date?
March 14
Pi Day, observed on March 14th (3/14), coincides with the first three significant digits of Pi and is celebrated by mathematicians and enthusiasts worldwide.
Q 06Which Greek mathematician approximated Pi by inscribing and circumscribing polygons?
Archimedes
Archimedes of Syracuse developed a method using polygons to approximate Pi, determining its value to be between 3 10/71 and 3 1/7.
Q 07Excluding the initial '3.', what are the first five digits that follow the decimal point in Pi?
14159
The decimal expansion of Pi begins with 3.14159, continuing infinitely without repeating.
Q 08Pi appears in which famous mathematical equation involving 'e', 'i', and '1'?
Euler's Identity
Euler's Identity, e^(iπ) + 1 = 0, often called the most beautiful equation in mathematics, connects five fundamental constants: e, i, π, 1, and 0.
Q 09How many digits of π did Rajveer Meena recite for his 2015 Guinness World Record?
70,000
Rajveer Meena recited 70,000 digits of π blindfolded at VIT University in Vellore, India, on 21 March 2015, a feat that took 9 hours 27 minutes and earned the Guinness World Record.
Q 10An Old Babylonian clay tablet implies π was taken as which fraction?
25/8
An Old Babylonian mathematical tablet from between the 19th and 17th centuries BCE shows an approximation of Pi as 25/8, which is 3.125.
Q 11The ancient Egyptian Rhind Papyrus implies an approximation of Pi close to which value?
3.16
The Rhind Papyrus (circa 1650 BCE) suggests an approximation of Pi as 256/81, which is approximately 3.16.
Q 12In the formula for the area of a circle, A = πr², what does 'r' represent?
Radius
The formula for the area of a circle is Pi times the square of its radius.
Q 13Which construction is impossible with compass and straightedge because Pi is transcendental?
Squaring the circle
The transcendence of Pi proves that the ancient problem of 'squaring the circle' – constructing a square with the same area as a given circle using only a compass and straightedge – is impossible.
Q 21What is the series π/4 = 1 − 1/3 + 1/5 − 1/7 + ..., known to Kerala mathematicians long before Europe, usually called?
Gregory-Leibniz Series
The Gregory-Leibniz series for Pi (π/4 = 1 - 1/3 + 1/5 - 1/7 + ...) was discovered by Madhava of Sangamagrama and later independently by James Gregory and Gottfried Leibniz.
Q 22Which capitalized Greek letter denotes the product of a sequence?
Pi (Π)
The uppercase Greek letter Π (Pi) is used in mathematics to denote a product of a sequence, similar to how Σ (Sigma) denotes summation.
Q 23Which famous physicist's birthday falls on Pi Day?
Albert Einstein
Albert Einstein was born on 14 March 1879 in Ulm, Germany; Princeton, New Jersey, where he lived from 1933 until his death in 1955, folds his birthday into its Pi Day festivities.
Q 14Pi is involved in the calculation of the volume for which common three-dimensional shape?
Sphere
The volume of a sphere is given by the formula V = (4/3)πr³, demonstrating Pi's role in three-dimensional geometry.
Q 15Pi Approximation Day honours which common fractional approximation of π?
22/7
Pi Approximation Day is celebrated on July 22nd (22/7) because the fraction 22/7 is a widely used and fairly accurate approximation of Pi.
Q 16Which mathematician popularised the use of π for the constant, though he didn't introduce it?
Leonhard Euler
Leonhard Euler used π for 3.14... in his 1736 Mechanica and his widely read 1748 Introductio in analysin infinitorum, and his fame made the symbol standard across Europe.
Q 17In what year was Pi Day first celebrated at the Exploratorium in San Francisco?
1988
Pi Day was founded in 1988 by physicist Larry Shaw at the Exploratorium, a science museum in San Francisco.
Q 18Which Persian astronomer computed π to 16 decimal digits in 1424, a record for about 180 years?
Jamshid al-Kashi
Jamshid al-Kashi, working at Samarkand, computed 2π to nine sexagesimal (base-60) places in 1424, equivalent to 16 decimal digits, using a polygon of 3×2^28, more than 800 million, sides.
Q 19The Greek letter π corresponds to which letter of the Latin alphabet?
P
π is the Greek letter pi, the counterpart of the Latin letter P; in Greek it carries the p sound, as at the start of Plato's name, Πλάτων.
Q 20Which Indian mathematician published dozens of fast-converging formulae for π in 1914?
Srinivasa Ramanujan
Srinivasa Ramanujan's 1914 paper 'Modular Equations and Approximations to π' gave rapidly converging series, one of which adds about eight correct digits per term and underlies the later Chudnovsky algorithm.
Q 24Chinese mathematicians in the 5th century AD approximated Pi to how many decimal places?
Seven
In the 5th century AD, Chinese mathematicians, notably Zu Chongzhi, approximated Pi to seven decimal places.
Q 25William Shanks hand-calculated 607 digits of π in 1853; at roughly which digit did his error begin?
The 528th
Shanks's error began at the 528th decimal place, so every later digit, including the 100 he added in 1873 to reach 707, was wrong; D. F. Ferguson spotted the mistake with a mechanical desk calculator in 1944.
Q 26The Borwein brothers' 1984 algorithm does what to the number of correct digits of π each step?
Quadruples it
The Borweins' 1984 iteration quadruples the number of correct digits of π at every step; three years later they published one that multiplies the count fivefold, at the cost of far more memory than a plain series needs.
Q 27Which Swiss mathematician first rigorously proved in the 1760s that Pi is irrational?
Johann Heinrich Lambert
His proof exploited a continued-fraction representation of the tangent function; transcendence would wait more than a century for Lindemann.
Q 28What is the definition of the circumference of a circle?
The distance around it
The distance around it is the circumference, the arc length of the full perimeter; the distance across through the centre is the diameter.
Q 29In the cylinder volume formula V = πr²h, what does 'h' represent?
Height
In the formula for the volume of a cylinder, V = πr²h, 'h' stands for the height of the cylinder.
Q 30In 1897 an amateur mathematician nearly got which Midwestern US state's legislature to pass a bill implying π = 3.2?
Indiana
Indiana's lower house passed the Pi Bill, whose author claimed to have squared the circle, fifteen years after Lindemann had proved that impossible.