Books Books
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

## Elements of Geometry, Containing the First Six Books of Euclid

Euclid - 1826 - 234 pages
...are right lines, it is called a rectilineal angle. 10. When a right line standing on another right line, makes the adjacent angles equal to one another,...each of the equal angles is a right angle, and the right line standing on the other is called a perpendicular. 11. An obtuse angle is that which is greater...

## Euclid's Elements of geometry, transl. To which are added, algebraic ...

Euclides - 1826 - 226 pages
...are right lines, it is called a rectilineal angle. 10. When a right line standing on another right line, makes the adjacent angles equal to one another,...each of the equal angles is a right angle, and the right Tine standing on the other is called a perpendicular. 11. An obtuse angle is that which is greater...

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

Robert Simson - Trigonometry - 1827 - 546 pages
...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, each of the angles is called a right angle; and the straight line which stands on the other is called a perpendicular...

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

Thomas Curtis - Aeronautics - 1829 - 814 pages
...the angle contained by the line С В and DB. 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 the straight line which stands on the other is called a PERPENDICULAR....

## Geometry Without Axioms; Or the First Book of Euclid's Elements. With ...

Thomas Perronet Thompson - Euclid's Elements - 1833 - 168 pages
...is always the direct angle that is meant. XXXVII. 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 Elements of Euclid: Viz. the First Six Books, Together with the Eleventh ...

Euclid - 1835 - 540 pages
...the angle ADG is equal0 to the angle GDB : But 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 :d Therefore the angle GDB is a right angle: But FDB is likewise a right angle;...

## The Teacher's Assistant in the "Course of Mathematics Adapted to the Method ...

Mathematics - 1836 - 488 pages
...together but are not in the same straight line. 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 the straight line which stands on the other is called a perpendicular...

## The Element of Geometry

John Playfair - Geometry - 1836 - 148 pages
...angle ADG is equal (7. 1.) to the angle BDG ; but 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 (Def. 27. 1.); therefore BDG is a right angle ; but BDF is likewise a right...