### „In any triangle the centre of gravity lies on the straight line joining any angle to the middle point of the opposite side.“

— Archimedes, buch On the Equilibrium of Planes

Book 1, Proposition 13.

On the Equilibrium of Planes

— Archimedes, buch On the Equilibrium of Planes

Book 1, Proposition 9.

On the Equilibrium of Planes

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— Archimedes, buch On the Equilibrium of Planes

Book 1, Proposition 13.

On the Equilibrium of Planes

— Archimedes, buch On the Equilibrium of Planes

Book 1, Proposition 4.

On the Equilibrium of Planes

— Archimedes, buch On the Equilibrium of Planes

Book 1, Proposition 10.

On the Equilibrium of Planes

— Archimedes, buch On the Equilibrium of Planes

Book 1, Proposition 14.

On the Equilibrium of Planes

— Archimedes, buch The Method of Mechanical Theorems

Proposition 6.

The Method of Mechanical Theorems

— Archimedes, buch The Method of Mechanical Theorems

Proposition presumed from previous work.

The Method of Mechanical Theorems

— Aristarchus of Samos ancient Greek astronomer and mathematician

p, 125

On the Sizes and Distances of the Sun and the Moon (c. 250 BC)

— Archimedes, buch The Method of Mechanical Theorems

of the portion adjacent to the base

Proposition presumed from previous work.

The Method of Mechanical Theorems

— Mark Twain American author and humorist 1835 - 1910

Quoting a schoolchild in "English as She Is Taught"

— Johannes Kepler, buch Astronomia nova

As quoted by Bryant, ibid.

Astronomia nova (1609)

— Arthur Schopenhauer, buch Parerga und Paralipomena

Vol. 2 "Further Psychological Observations" as translated in Essays and Aphorisms (1970), as translated by R. J. Hollingdale

Parerga and Paralipomena (1851), Counsels and Maxims

And walk straight down the middle of it.“

— Kate Bush British recording artist; singer, songwriter, musician and record producer 1958

Song lyrics, The Sensual World (1989)

— Yahia Lababidi 1973

Signposts to Elsewhere (2008)

— Madeleine L'Engle American writer 1918 - 2007

Quelle: A Wrinkle in Time: With Related Readings

— Will Durant American historian, philosopher and writer 1885 - 1981

Quelle: The Story of Philosophy: The Lives and Opinions of the World's Greatest Philosophers

— Theodor W. Adorno, buch Minima Moralia

Nun gilt für die kürzeste Verbindung zwischen zwei Personen die Gerade, so als ob sie Punkte wären.

E. Jephcott, trans. (1974), § 20

Minima Moralia (1951)

"If all points of the straight line fall into two classes such that every point of the first class lies to the left of every point of the second class, then there exists one and only one point which produces this division of all points into two classes, this severing of the straight line into two portions."

…every one will at once grant the truth of this statement; the majority of my readers will be very much disappointed in learning that by this commonplace remark the secret of continuity is to be revealed.“

— Richard Dedekind German mathematician 1831 - 1916

Stetigkeit und irrationale Zahlen (1872)

— Helen Thomas American author and journalist 1920 - 2013

Interview by Adam Holdorf for Real Change News, (18 March 2004).

— Hans Freudenthal Dutch mathematician 1905 - 1990

Quelle: Mathematics as an Educational Task (1973), p. 133

— Morris Kline American mathematician 1908 - 1992

Quelle: Mathematical Thought from Ancient to Modern Times (1972), p. 175

Kontext: To avoid any assertion about the infinitude of the straight line, Euclid says a line segment (he uses the word "line" in this sense) can be extended as far as necessary. Unwillingness to involve the infinitely large is seen also in Euclid's statement of the parallel axiom. Instead of considering two lines that extend to infinity and giving a direct condition or assumption under which parallel lines might exist, his parallel axiom gives a condition under which two lines will meet at some finite point.