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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.
Euclid's Elements of plane geometry [book 1-6] explicitly enunciated, by J ... - Page 3
by Euclides - 1860

## Euclid's Elements of Geometry: From the Latin Translation of Commandine. To ...

Euclid, John Keill - Geometry - 1723 - 442 pages
...the Angle AFE j. g ti fhall bef equal to the Angle BFE. But when a Right Line {landing upon a Right Line makes the adjacent Angles equal to one another, each of the equal Angles is ia Right Angle. Wherefore AFE, or BFE, is a Right Angle. And therefore the Right Line...

## Euclid's Elements of Geometry,: From the Latin Translation of Commandine. To ...

Euclid, John Keill - Geometry - 1733 - 448 pages
...Therefore the Angle * 8- i. AD G is * equal to the Angle GD B. But when a Right Line ftanding upon 'a Right Line, makes the adjacent Angles equal to one another, each of the 10. i. equal Angles will f be a Right Angle. Wherefore the Angle GDB is a Right Angle. But FDB is alfo...

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

Robert Simson - Trigonometry - 1762 - 466 pages
...the angle ADG is equal c to the angle GDB. but when a ftraight line ftanding upon another ftraight line, makes the adjacent angles equal to one another ,each of the angles is a right angle *. therefore the angle GDB is a right angle. but FDB is like- d.io.Def.i. wife a right...

## Euclid's Elements of Geometry: The First Six, the Eleventh and Twelfth Books

Euclid - Geometry - 1765 - 464 pages
...angle EH c [by prop. 8.] ; and thefe are adjacent angles. But when a right line flanding upon a right line makes the adjacent angles equal to one another, each of the equal angles is a right angle, and the ftanding right line is called a perpendicular to that upon which...

## Instructions Given in the Drawing School Established by the Dublin Society ...

Joseph Fenn - Mathematics - 1769 - 536 pages
...When a ftraight line (AB) {landing on another ftright line (CD) makes the adjacent angles (ABD, ABC,) equal to one another, each of the angles is called a right angle ; and the rtraight line (AB) which ftands on the other (CD) is called я perpendicular. Fig. 7. XI. An Obtvfe...

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

Robert Simson - Trigonometry - 1775 - 520 pages
...is equal c to the angle GDB: But when a ftraight line ftanding upon another ftraight line makes .A. the adjacent angles equal to one another, each of the angles is a right angle d : Therefore the angle GDB is a " d to. def. i« right angle : But FDB is likewife a...

## The First Six Books: Together with the Eleventh and Twelfth

Euclid - 1781 - 550 pages
...is equal e to the angle GDB : Buk when a ftraight line flanding upon another ftraight line makes A the adjacent angles equal to one another, each of the angles is a right an. J£ gled: Therefore the angle GDB is a * dio.def.r. Tight angle : But FDB is likewife a...

## The Elements of Euclid: With Dissertations Intended to Assist and Encourage ...

Euclid, James Williamson - Euclid's Elements - 1781 - 324 pages
...8. i.) the angle AFE is equal to the angle BFE : but when a ftraight line ftanding upon a ftraight line makes the adjacent angles equal to one another, each of the equal angles is a right angle ; therefore each of the angles AFE, BFE is a right angle : therefore...

## Observations on the Nature of Demonstrative Evidence: With an Explanation of ...

Thomas Beddoes - Geometry - 1793 - 196 pages
...whether they are plane or otherwife. DEFINITION X, When a Jlfaight line ftanding on another Jiraight line makes the adjacent angles equal to one another,...each of the angles is called a right angle, and the line which Jlands on the other is called a perpendicular to it. Here we have an appeal made to the...

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

John Playfair - Euclid's Elements - 1795 - 444 pages
...the angle ADG is equal c. ,to the angle GDB : But when a ftraight line flanding upon another ftraight line makes the adjacent angles equal to one another, each of the angles is a right angle d. d7def.i. Therefore the angle GDB is a right angle : But FDB is .likewife a right angle...