Books Books
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.
The Elements of geometry; or, The first six books, with the eleventh and ... - Page 2
by Euclides - 1855

## Elements of Geometry: Containing the First Six Books of Euclid: With a ...

John Playfair - 1819 - 317 pages
...contained by BD, CB is called the angle DBC, or CBD ; but, if there be only one angle at a point, it may be expressed by a letter placed at that point ; as the angle at E.' VII. When a straight line standing on another straight line makes the adjacent angles equal to one...

## Elements of Geometry: Containing the First Six Books of Euclid, with a ...

John Playfair - Euclid's Elements - 1819 - 333 pages
...therefore the angle ADG is equal (8. 1.) to the angle GDB : Bat when a straight line standing upon another straight line makes the adjacent angles equal to one another, each of the angles is a right angle (7. def. 1.). Therefore the angle GDB is a right angle: But FDB is likewise...

## Elementary Illustrations of the Celestial Mechanics of Laplace: Part the ...

Pierre Simon marquis de Laplace, Thomas Young - Celestial mechanics - 1821 - 388 pages
...described by three letters placed near the lilies, the middle letter at the angular point % 64. DEFINITION. When a straight line standing on another straight line makes the adjacent angles equal, they are called right angles. 65. DEFINITION. A straight line between two right angles is called a...

## A Popular Course of Pure and Mixed Mathematics ...: With Tables of ...

Peter Nicholson - Mathematics - 1825 - 372 pages
...contained by DB. CB, is called the angle DBC, o. CBD j but if thtie be only one angle at a point, it may be expressed by a letter placed at that point ; as the angle at E.' 10. When a straight line standing on another straight line makes the adjacent angles equal to one another,...

## Elements of Arithmetic, Algebra, and Geometry

George Lees - 1826 - 266 pages
...by BD, CB, is called the angle DEC, or CBD ; but, if there be only one angle at a point, it may be expressed by a letter placed at that point ; as the angle at E. VII.— When a straight line AB, standing on another straight line CD, makes the adjacent angles ABC...

## The Elements of Euclid: The Errors by which Theon, Or Others, Have Long ...

Robert Simson - Trigonometry - 1827 - 513 pages
...' DB, CB, is called the angle DBC, or CBD ; but, if ' there be only one angle at a point, it may be expressed ' by a letter placed at that point : as the angle at E.' X. When a straight line standing on another straight line makes the adjacent angles equal to one another,...

## A London Encyclopaedia, Or Universal Dictionary of Science, Art ..., Volume 10

Thomas Curtis - Aeronautics - 1829 - 814 pages
...that form the angle, thus С ü D or D В С denotes the angle contained by the line С В and DB. 7. When a straight line standing on another straight...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....

## Elements of Geometry: Being Chiefly a Selection from Playfair's Geometry

John Playfair - Geometry - 1829 - 186 pages
...contained by Bl), CB, is called the angle DBC1, or CBD. If there be only one angle at a point, it may be expressed by a letter placed at that point, as -the angle at E. 10. When a straight line standing on another straight line makes the adjacent angles equal to each...