Books Books From this it is manifest, that if one angle of a triangle be equal to the other two, it is a right angle, because the angle adjacent to it is equal to the same two; and when the adjacent angles are equal, they are right angles. A Royal Road to Geometry: Or, an Easy and Familiar Introduction to the ... - Page 178
by Thomas Malton - 1774 - 440 pages ## The Elements of Euclid: The Errors, by which Theon, Or Others, Have Long Ago ...

Robert Simson - Trigonometry - 1762 - 466 pages
...fegment is faid to be lefs thai} ' a right angle.' COR. From this it is manifeft, that if one angle pf a triangle be equal to the other two, it is a right angle, becaufe the angle adjacent to it is equal to the fame two ; and when the adjacent angles arc equal,... ## The Elements of Euclid, Viz: The Errors, by which Theon, Or Others, Have ...

Robert Simson - Trigonometry - 1775 - 520 pages
...of the left « fegment is faid to be lefs, than a right angle.' CoR. From this it is manifeft, that if one angle of a triangle be equal to the other two, it is a right angle, becaufe the angle adjacent to it is equal to the fame two ; and when the adjacent angles are equal,... ## The Elements of Euclid: In which the Propositions are Demonstrated in a New ...

Euclid - Geometry - 1776 - 324 pages
...in an lequilateral triangle is one third of two right angles, or two thirds of one right angle. 6. If one angle of a triangle be equal to the other two, that angle is a right one ; for, if the fide is produced, the adjacent angle is equal to the other... ## The Elements of Euclid,: In which the Propositions are Demonstrated in a New ...

Euclid - Geometry - 1776 - 318 pages
...in an ^equilateral triangle is one third of two right angles, or two thirds of one right angle. 6. If one angle of a triangle be equal to the other two, that angle is a right one ; for, if the fide is produced, the adjacent angle is equal to the other... ## The Elements of Euclid: With Dissertations Intended to Assist and Encourage ...

Euclid, James Williamson - Euclid's Elements - 1781 - 324 pages
...wherefore the angle BAC is a right angle. Which was to be demonftrated. Cor From this it is manifeft that if one angle of a triangle be equal to the other two it is a right angle : for this reafon becaufe the adjacent angle is equal to the fame two : but (by def. 10. i.) when the... ## The First Six Books: Together with the Eleventh and Twelfth

Euclid - 1781 - 550 pages
...angle of thelcfa ' fegment is faid to be lefs, than a right angle.' CoR. From this it is manifeft, that if one angle of a triangle be equal to the other two, it is a right angle, becaufe the angle adjacent to it is equal to the fame two ; and when the ad jacent angles are equal,... ## The Elements of Euclid: The Errors, by which Theon, Or Others, Have Long Ago ...

Robert Simson - Trigonometry - 1781 - 466 pages
...of the lefs feg~ient is faid to be lefs .' than a right angle.' CoR. From this it is Tnanifcit, that if one angle of a triangle be equal to the other two, it is a right angle, becaufe the angle Adjacent to it is equal to the fame two ; and when the adjacent angles are equal,... ## The Elements of Euclid: Also the Book of Euclid's Data ...cor. viz. The ...

Robert Simson - Trigonometry - 1804
...angle of the lefs fegment is faid to be lefs * than a right angle.' CoR. From this it is manifeft, that if one angle of a triangle be equal to the other two, it is a right angle, becaufe the angle adjacent to it is equal to the fame two ; and when the adjacent angles are equal,... ## Elements of Geometry: Containing the First Six Books of Euclid, with a ...

John Playfair - Euclid's Elements - 1806 - 320 pages
...right angle. Therefore, in a circle, Book in. &c. QED COR. From the demonstration it is manifest that if one angle of a triangle be equal to the other two angles, it is a right angle. PROP. XXXII. THEOR. IF a straight line touch a circle, and from the point... 