Q 01/05

A famous run of six consecutive 9s in the decimal expansion of π starts at roughly which decimal place?

A) The 762nd

B) The 100th

C) The 2,015th

D) The 31,415th

Answer · why

A) 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...

Q 02/05

Which Welsh mathematician first used the Greek letter π for the circle constant, in a 1706 book?

A) Robert Recorde

B) William Jones

C) Edmond Halley

D) Isaac Newton

Answer · why

B) William Jones

William Jones printed π in his 1706 Synopsis Palmariorum Matheseos but credited its formulas to the 'ready pen' of John Machin, so some suspect Machin...

Q 03/05

Which mathematical property of pi means its decimal expansion is infinite and non-repeating?

A) Rational

B) Irrational

C) Algebraic

D) Perfect

Answer · why

B) Irrational

Irrational numbers cannot be written as one whole number over another; every such fraction's decimal either stops or repeats, as 1/3 = 0.333... does, ...

Q 04/05

Pi is transcendental: not the root of any non-zero polynomial with which type of coefficients?

A) Complex

B) Real

C) Rational

D) Irrational

Answer · why

C) Rational

Rational coefficients are the test: √2 solves x² − 2 = 0, so it is merely algebraic, while π solves no such equation; Cantor showed in 1874 that almos...

Q 05/05

Pi Day is celebrated annually on which date?

A) March 14

B) April 15

C) January 1

D) July 22

Answer · why

A) March 14

March 14 is written 3/14 in American date order, matching π's first three digits; the day began in 1988 as a staff party at a science museum, with fru...