Etymology of the Word HypotenuseDate: 01/26/2003 at 13:18:39 From: David Goldberg Subject: Hypotenuse Why is the hypotenuse called "hypotenuse"? "hypo" means "under," "tenuse" I think comes from "tenein," "to stretch." Then "hypotenuse" came from "stretch under." Does it refer to roof supports in ancient Greek buildings? That is just a guess. Date: 01/26/2003 at 15:21:08 From: Doctor Sarah Subject: Re: Hypotenuse Hi David - thanks for writing to Dr. Math. From Steven Schwartzman's _The Words of Mathematics, An Etymological Dictionary of Mathematical Terms used in English_ (Mathematical Association of America): hypotenuse from Greek-derived hypo- "under" and teinein "to stretch." The Latin cognates, which may be more familiar, are sub for "under" and tendere, "to stretch," as combined in subtend. The Indo-European root underlying Greek teinein is ten- "to stretch." A Native English cognate is the adjective thin, which describes an object that has been stretched. When a right angle is inscribed in a circle, the diameter of the circle subtends that right angle. The diameter automatically becomes the hypotenuse of the right triangle thus formed. Even when a right triangle is not inscribed in a circle, the hypotenuse is the side that "stretches" from one leg to the other. - Doctor Sarah, The Math Forum http://mathforum.org/dr.math/ Date: 01/26/2003 at 20:22:56 From: David Goldberg Subject: Thank you (Hypotenuse) Thanks much Dr. Sarah, for finding the etymology of "Hypotenuse" - it has been bugging me for a few years - I sometimes suggest to my (community college) students the task of researching this, but no one ever did. In a similar vein, they are amused to discover why "quadratic," Latin base meaning "four," means a polynomial of degree (only) two. It makes a nice tie between geometry and algebra. Thanks again! David Goldberg |
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