 When a straight line standing on another straight line makes the adjacent angles equal to one another, each of the angles is called a right angle ; and the straight line which stands on the other is called a perpendicular to it.  Elements of Geometry and Conic Sections - Page 10by Elias Loomis - 1857 - 226 pagesFull view - About this book
 | William P. Berlinghoff, Kerry E. Grant, Dale Skrien - Mathematics - 2001 - 672 pages
...describe familiar figures in more or less familiar ways. For example: « When a straight line crossing a straight line makes the adjacent angles equal to one another, each of the equal angles is called a right angle, and the straight line crossing the other is called a perpendicular... | |
 | Audun Holme - Mathematics - 2002 - 408 pages
...containing the angle are straight, the angle is caller rectilinear. 9. When a straight line set up on a straight line makes the adjacent angles equal to one another, each of the angles is right, and the straight line standing on the other is called the perpendicular to the... | |
 | Jean Christianidis - Mathematics - 2004 - 502 pages
...BA is perpendicular to AT and Definition I.10, which states that “When a straight line set up on a straight line makes the adjacent angles equal to one another, each of the right angles is right, and the straight line standing on the other is called a perpendicular to... | |
 | Paolo Mancosu, Klaus Frovin Jørgensen, Stig Andur Pedersen - Mathematics - 2005 - 336 pages
...classes of (rectilinear) angles (trans. Heath 1926, I, 181): 1 0. When a straight line set up on a straight line makes the adjacent angles equal to one another, each of the equal angles is right [...]. 1 1 . An obtuse angle is an angle greater than a right angle. 12.... | |
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