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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

## A course of practical geometry for mechanics

W. PEASE - 1846 - 86 pages
...of two of its great circles. When an angle is mentioned simply, it means a rectilineal angle. 23*. 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...

## The Elements of Euclid, the parts read in the University of Cambridge [book ...

Euclides - 1846 - 292 pages
...contained by DB, CB, is named the angle DBC or CBD: but, if there be only one angle at a point, it may ba 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...

## The Elements of Geometry, Symbolically Arranged

Great Britain. Admiralty - Geometry - 1846 - 130 pages
...contained by DB, 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. X. angle; and the straight line which stands on the other, is called a perpendicular to it. XI....

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

John Playfair - Euclid's Elements - 1846 - 332 pages
...1 BD, CB, is called the angle DBC, or CBD ; but, if there be only one an1 gle at a point, it may be expressed by a letter placed at that point ; as the ' angle at £.' 7. When a straight line standing on another straight line makes the adjacent angles equal to one...

## The First Book of Euclid's Elements, Simplified, Explained, and Illustrated ...

Euclides - 1847 - 128 pages
...of the lines, by the meeting of which they are formed. See the Observation after Definition 18. 10. When a straight line, standing on another straight line, makes the adjacent an. gles equal to one another, each of the angles is called a right angle; and the straight line which...

## The definitions, postulates, axioms, and enunciations of the propositions of ...

Euclides - 1848 - 52 pages
...inclination of two straight lines to one another, which meet together, but are not in the same straight line. X. When a straight line standing on another straight line, makes the adjacent angles equal to each other, each of these angles is called a right angle ; and the straight line which stands on the...

## Lessons on the delineation of form

Charles Richson - 1848 - 98 pages
...two straight lines to one another, which meet together, but are not in the same straight line." 2. "When a straight line standing on another straight line makes the adjacent angles equal to each other, each of these angles is called a right angle; and the straight line which stands on the...

## The first three books of Euclid's Elements of geometry, with theorems and ...

Euclid, Thomas Tate - 1849 - 120 pages
...one angle at a point, it may be expressed by a letter placed at that point; as the ;ingle at E." ' x. 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...