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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, and the straight line standing on the other is called a perpendicular to that on which it stands.
The Elements of Euclid: With Dissertations Intended to Assist and Encourage ... - Page 15
by Euclid, James Williamson - 1781 - 309 pages

## The Elements of Euclid for the Use of Schools and Colleges: Comprising the ...

Euclid, Isaac Todhunter - Euclid's Elements - 1883 - 428 pages
...angle AFE is equal to the angle BFE. [I. 8. But 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 ; [I. Definition 10. therefore each of the angles AFE, BFE is a right...

## Geometry for schools, comprising books i. and ii. of Euclid, with some ...

Euclides - 1883 - 176 pages
...; name also two vertically opposite angles. H 7. 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 each of the lines is perpendicular to the other, or at right angles...

## Stewart's specific subjects. Euclid. [1st] (-3rd stage). [With 2 issues of ...

Stewart W. and co - 1884 - 272 pages
...named from three or one letters, as ABC or B. X. 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...

## Elementary Physiography: An Introduction to the Study of Nature

John Thornton - Physical geography - 1888 - 266 pages
...the following definition of a right angle : — ' 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...

## The Harpur Euclid: An Edition of Euclid's Elements

Edward Mann Langley, W. Seys Phillips - 1890 - 538 pages
...instead of it. See Note 2 on Prop. 9. DEF. 10. — 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 said to be perpendicular,...

## A Text-book of Euclid's Elements for the Use of Schools. Books I.-VI ..., Book 1

Euclid, Henry Sinclair Hall, Frederick Haller Stevens - Euclid's Elements - 1900 - 330 pages
...are also vertically opposite to one another. 10. 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...

## A Text-book of Euclid's Elements for the Use of Schools, Book 1

Euclid - Euclid's Elements - 1904 - 488 pages
...are also vertically opposite to one another. 10. 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...

## Modern Sheet-metal Workers' Instructor: Practical Geometry, Mensuration ...

Joseph H. Rose - Sheet-metal work - 1906 - 340 pages
...same straight line as in Fig. 1. Fig. 1. Fig. 2. 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...