3 (THREE; /ˈθriː/ ) is a number , numeral , and glyph . It is the natural number following 2 and preceding 4 . CONTENTS * 1 Evolution of the glyph * 1.1 Flat top 3 * 2 In mathematics * 2.1 In numeral systems * 2.2 List of basic calculations * 3 In science * 3.1 In protoscience * 3.2 In pseudoscience * 4 In philosophy * 5 In religion * 5.1 In
Christianity
* 6 In sports * 7 See also * 8 References * 9 External links EVOLUTION OF THE GLYPH Three is the largest number still written with as many lines as the
number represents. (The Ancient Romans usually wrote 4 as IIII, but
this was almost entirely replaced by the subtractive notation IV in
the Middle Ages.) To this day 3 is written as three lines in Roman and
Chinese numerals . This was the way the
Brahmin
While the shape of the 3 character has an ascender in most modern typefaces , in typefaces with text figures the character usually has a descender , as, for example, in . In some French textfigure typefaces, though, it has an ascender instead of a descender. FLAT TOP 3 A common variant of the digit 3 has a flat top, similar to the character Ʒ (ezh ). This form is sometimes used to prevent people from fraudulently changing a 3 into an 8. It is usually found on UPCA barcodes and standard 52card decks . IN MATHEMATICS 3 is: * a rough approximation of π (3.1415...) and a very rough
approximation of e (2.71828..) when doing quick estimates.
* the number of noncollinear points needed to determine a plane and
a circle .
* the first odd prime number and the second smallest prime.
* the first
Fermat prime (22n + 1).
* the first
Mersenne prime (2n − 1).
* the second
Sophie Germain prime .
* the second
Mersenne prime exponent.
* the second factorial prime (2! + 1).
* the second
Lucas prime .
* the second triangular number . It is the only prime triangular
number.
* the fourth
Fibonacci number
Three is the only prime which is one less than a perfect square . Any other number which is n2 − 1 for some integer n is not prime, since it is (n − 1)(n + 1). This is true for 3 as well (with n = 2), but in this case the smaller factor is 1. If n is greater than 2, both n − 1 and n + 1 are greater than 1 so their product is not prime. A natural number is divisible by three if the sum of its digits in base 10 is divisible by 3. For example, the number 21 is divisible by three (3 times 7) and the sum of its digits is 2 + 1 = 3. Because of this, the reverse of any number that is divisible by three (or indeed, any permutation of its digits) is also divisible by three. For instance, 1368 and its reverse 8631 are both divisible by three (and so are 1386, 3168, 3186, 3618, etc.). See also Divisibility rule . This works in base 10 and in any positional numeral system whose base divided by three leaves a remainder of one (bases 4, 7, 10, etc.). Three of the five Platonic solids have triangular faces – the tetrahedron , the octahedron , and the icosahedron . Also, three of the five Platonic solids have vertices where three faces meet – the tetrahedron , the hexahedron (cube ), and the dodecahedron . Furthermore, only three different types of polygons comprise the faces of the five Platonic solids – the triangle , the square , and the pentagon . There are only three distinct 4×4 panmagic squares . According to
Pythagoras
The trisection of the angle was one of the three famous problems of antiquity.
Gauss
IN NUMERAL SYSTEMS There is some evidence to suggest that early man may have used counting systems which consisted of "One, Two, Three" and thereafter "Many" to describe counting limits. Early peoples had a word to describe the quantities of one, two, and three but any quantity beyond was simply denoted as "Many". This is most likely based on the prevalence of this phenomenon among people in such disparate regions as the deep Amazon and Borneo jungles, where western civilization's explorers have historical records of their first encounters with these indigenous people. LIST OF BASIC CALCULATIONS MULTIPLICATION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 50 100 1000 10000 3 × X 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 150 300 3000 30000 DIVISION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 3 ÷ X 3 1 .5 1 0 .75 0.6 0.5 0.428571 0.375 0.3 0.3 0.27 0.25 0.230769 0.2142857 0.2 0.1875 0.17647058823529411 0.16 0.157894736842105263 0.15 X ÷ 3 0.3 0.6 1 1.3 1.6 2 2.3 2.6 3 3.3 3.6 4 4.3 4.6 5 5.3 5.6 6 6.3 6.6 EXPONENTIATION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 3X 3 9 27 81 243 729 2187 6561 19683 59049 177147 531441 1594323 4782969 14348907 43046721 129140163 387420489 1162261467 3486784401 X3 1 8 27 64 125 216 343 512 729 1000 1331 1728 2197 2744 3375 4096 4913 5832 6859 8000 IN SCIENCE * The Roman numeral III stands for giant star in the Yerkes spectral
classification scheme .
* Three is the atomic number of lithium .
* Three is the
ASCII
IN PROTOSCIENCE * In European alchemy , the three primes (Latin: tria prima) were salt ( ), sulfur ( ) and mercury ( ). * The three doshas (weaknesses) and their antidotes are the basis of Ayurvedic medicine in India. IN PSEUDOSCIENCE * Three is the symbolic representation for Mu , Augustus Le Plongeon 's and James Churchward 's lost continent. IN PHILOSOPHY Main article: Trichotomy (philosophy) * Philosophers such as
Aquinas , Kant ,
Hegel
IN RELIGION See also: Triple deity Many world religions contain triple deities or concepts of trinity, including: * the
Hindu
The Shield of the
Trinity
IN CHRISTIANITY * The threefold office of Christ is a Christian doctrine that Christ
performs the functions of prophet , priest , and king .
* The ministry of Jesus lasted approximately three years (2730 AD).
* During the
Agony in the Garden
IN JUDAISM *
Noah
IN BUDDHISM * The Triple
Bodhi
IN SHINTO * The Imperial Regalia of Japan of the sword, mirror, and jewel. IN TAOISM * The Three Treasures (Chinese : 三寶; pinyin : sānbǎo;
Wade–Giles : sanpao), the basic virtues in
Taoism
IN HINDUISM * The
Trimurti
IN ZOROASTRIANISM * The three virtues of Humata, Hukhta and Huvarshta (Good Thoughts,
Good Words and Good Deeds) are a basic tenet in
Zoroastrianism
IN NORSE MYTHOLOGY Three is a very significant number in
Norse mythology
* Prior to
Ragnarök
IN OTHER RELIGIONS * The Wiccan Rule of Three .
* The Triple Goddess : Maiden, Mother, Crone; the three fates.
* The sons of
Cronus
IN ESOTERIC TRADITION * The
Theosophical Society
AS A LUCKY OR UNLUCKY NUMBER This section NEEDS ADDITIONAL CITATIONS FOR VERIFICATION . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed. (April 2009) (Learn how and when to remove this template message ) Three (三, formal writing: 叁, pinyin sān,
Cantonese
Counting to three is common in situations where a group of people wish to perform an action in synchrony : Now, on the count of three, everybody pull! Assuming the counter is proceeding at a uniform rate, the first two counts are necessary to establish the rate, and the count of "three" is predicted based on the timing of the "one" and "two" before it. Three is likely used instead of some other number because it requires the minimal amount counts while setting a rate. In East and
Southeast Asia
There is another superstition that it is unlucky to take a third light , that is, to be the third person to light a cigarette from the same match or lighter. This superstition is sometimes asserted to have originated among soldiers in the trenches of the First World War when a sniper might see the first light, take aim on the second and fire on the third. The phrase "Third time\'s the charm" refers to the superstition that after two failures in any endeavor, a third attempt is more likely to succeed. This is also sometimes seen in reverse, as in "third man gets caught".
Luck
IN SPORTS * In association football a team that wins three trophies in a season is said to have won a treble . * In baseball scorekeeping, "3" denotes the first baseman. * In basketball , the "3 position" is the small forward . * In bowling , three strikes bowled consecutively is known as a "turkey". * In professional wrestling , a pin is when one's shoulders are held the opponent's shoulders against the mat for a count of three. * A "threepeat " is a term for winning three consecutive championships. * A triathlon consists of three events: swimming, bicycling, and running. * In many sports a competitor or team is said to win a Triple Crown if they win three particularly prestigious competitions. SEE ALSO * Mathematics portal *
Cube
REFERENCES * ^ Georges Ifrah, The Universal History of Numbers: From Prehistory to the Invention of the Computer transl. David Bellos et al. London: The Harvill Press (1998): 393, Fig. 24.63 * ^ Priya Hemenway (2005), Divine Proportion: Phi In Art, Nature, and Science, Sterling Publishing Company Inc., pp. 53–54, ISBN 1402735227 * ^ Big Numbers. ISBN 1840464313 . * ^ "Most stable shape triange". Maths in the city. Retrieved February 23, 2015. * ^ Eric John Holmyard. Alchemy. 1995. p.153 * ^ Walter J. Friedlander. The golden wand of medicine: a history of the caduceus symbol in medicine. 1992. p.7677 * ^ Churchward, James (1931). "The Lost Continent of Mu – Symbols, Vignettes, Tableaux and Diagrams". Biblioteca Pleyades. Retrieved 20160315. * ^ Marcus, Rabbi Yossi (2015). "Why are many things in Judaism done three times?". Ask Moses. Retrieved 16 March 2015. * ^ "Shabbat". Judaism 101. 2011. Retrieved 16 March 2015. * ^ Kitov, Eliyahu (2015). "The Three Matzot". Chabad.org. Retrieved 16 March 2015. * ^ Kaplan, Rabbi Aryeh (28 August 2004). "Judaism and Martyrdom". Aish.com. Retrieved 16 March 2015. * ^ "The Basics of the Upsherin: A Boy\'s First Haircut". Chabad.org. 2015. Retrieved 16 March 2015. * ^ "The Conversion Process". Center for Conversion to Judaism. Retrieved 16 March 2015. * ^ Kaplan, Aryeh. "The Soul". Aish. From The Handbook of Jewish Thought (Vol. 2, Maznaim Publishing. Reprinted with permission.) September 4, 2004. Retrieved February 24, 2015. * ^ James G. Lochtefeld, Guna, in The Illustrated Encyclopedia of Hinduism: AM, Vol. 1, Rosen Publishing, ISBN 9780823931798 , page 265 * ^ See "bad" in the Oxford Dictionary of Phrase and Fable, 2006, via Encyclopedia.com. * Wells, D. The Penguin Dictionary of Curious and Interesting Numbers London: Penguin Group. (1987): 46–48 EXTERNAL LINKS Look up THREE in Wiktionary, the free dictionary.
