Celebrate Pi Day!

Learn these words relating to Pi, the mathematical constant and the 16th letter of the Greek alphabet. Pi Day is celebrated on March 14th, or 3/14, the date that corresponds to the first (and most well-known) digits in the decimal form of Pi.
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Full list of words from this list:

words only definitions & notes
  1. pi
    the ratio of the circumference to the diameter of a circle
    Memorizing pi is an undeniably nerdy pursuit, but some people have taken the challenge to extreme lengths.
  2. constant
    a number representing a quantity with a fixed value
    March 14 is typically batted about as "Pi Day" in pop culture as the date abbreviates to 3/14 or 3.14, matching the first three digits of the mathematical constant.
  3. ratio
    the relative magnitudes of two quantities
    Pi is the ratio of the circumference of a circle to its diameter. It's rounded up because the actual ratio has been calculated to over one trillion digits beyond the decimal point (which sounds like fun to read while swiping on a phone).
  4. circumference
    the length of the closed curve of a circle
    Defined as the ratio of the circumference of a circle to its diameter, π is one of the weirder numbers going.
  5. diameter
    the length of a straight line through the center of a circle
    The largest ice balls were some 3 inches in diameter — the size of a tea cup — and were recorded in Howard County, Texas.
  6. irrational number
    a real number that cannot be expressed as a rational number
    Even his studio is named for π, an “irrational number” that could be calculated for infinity without coming to a finite conclusion.
  7. geometry
    the mathematics of points and lines and curves and surfaces
    Classical geometry—Greek for “earth measure”—is not very earthly.
  8. digit
    one of the elements that form a system of numeration
    People have enjoyed memorising the digits in pi since at least the beginning of the 19th century. Back then only a few hundred digits were known, so it was barely more of a challenge than memorising a long poem.
  9. irrational
    a number that cannot be expressed as a quotient of integers
    Because pi is an irrational, or transcendental number, it continues infinitely without pattern or repetition, no matter how many digits beyond its decimal point you calculate.
  10. approximation
    a rough calculation of quantity or degree or worth
    Between 3,000 and 4,000 years ago, people used trial-and-error approximations of pi, without doing any math or considering potential errors.
  11. infinite
    having no limits or boundaries in time or space
    School teachers indoctrinate kids with the idea that pi wanders on forever behind its decimal. 3.1415926535…and beyond. But there are plenty of numbers with infinite digits. For example, 18, which has an infinite number of zeros behind it in decimal notation.
  12. decimal
    a number in a system based on ten
    Pi can be calculated out to an infinite number of decimals, but the first five digits are 3.1415.
Created on Mon Mar 13 20:12:41 EDT 2017 (updated Thu Feb 13 12:47:50 EST 2020)

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