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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

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

John Keill - Logarithms - 1723 - 444 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 CD drawn thro*...

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

Euclid, John Keill - Geometry - 1733 - 444 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 - 488 pages
...therefore 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...

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

Euclid - Geometry - 1765 - 492 pages
...will be equal to the angle BFE. But fmce a right line flanding upon a right line makes the adjoining 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, and fo the right line c D drawn thro' A\...

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

John Keill - Geometry - 1772 - 462 pages
...the Angle AFE fliall be f equal to the Angle BFE. But when af 8. t. Right Line Standing upon a Right Line makes the adjacent Angles equal to one another, each of the equal Angles is J a Right Angle. Wherefore AFE, orJ0«/. 10. i« BFE, is a Right Angle. And therefore the Right •Line...

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

Robert Simson - Trigonometry - 1775 - 534 pages
...is equal' to the angle CHG; and they are adjacent angles ; but when a ftraight line ftanding cet on a ftraight line makes the adjacent angles equal to one another, each of them is a right angle, and the ftraight line which flands upon the other is called a perpendicular...

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

Robert Simson - Trigonometry - 1781 - 534 pages
...equal e to the angle CHG; and they are adjacentc. 8. i. angles. but when a ftraight line ftanding on a ftraight line makes the adjacent angles equal to one another, each of them is aright angle, and the ftraight linewhich ftands upon the other is called a perpendiculartoit....

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

Euclid - 1781 - 552 pages
...by a 'letter placed at that point; as the Angle at E.' .X. When a ftraight line flanding on another ftraight line makes the adjacent angles equal to one another, each of the angles is called a right angle ; and the ftraight line which ftands on the other is called a perpendicular...