 | Euclides - 1834 - 518 pages
...the base CG: therefore the angle CHF is equal* to the angle CHG ; and they are adjacent angles: but when a straight line, standing on another straight...the adjacent angles equal to one another, each of them is a right angle, and the straight line. which stands upon the other, is called a perpendicular... | |
 | Euclid - 1835 - 540 pages
...contained by BD, CB is called the angle DBC, or CBD : but if there be only one angle at a point, it may be expressed by a letter placed at that point ; as the angle at E.' X. When a straight line standing on another straight line makes the adja- • cent angles equal to... | |
 | Mathematics - 1835 - 684 pages
...letter, as A, always denotes the angular point. 10. (Eue. i. det 10.) When a straight line standing; upon another straight line makes the adjacent angles equal to one another, each of them is called a right angle, and the straight line which stands upon the other is called a perpendicular... | |
 | Mathematics - 1836 - 488 pages
...of two straight lines to one another, which meet together but are not in the same straight line. 7. When a straight line standing on another straight...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... | |
 | John Playfair - Euclid's Elements - 1836 - 488 pages
...angle at a point, it may be expressed by a letter placed ' at that point ; as the angle at E.' VII. When a straight line standing on another straight line makes the adjacent angles equal to one an, other, each of the angles is called a right angle; and the straight line which stands on the other... | |
 | John Playfair - Geometry - 1836 - 148 pages
...therefore the 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... | |
 | Euclid, James Thomson - Geometry - 1837 - 410 pages
...meet one another.^ The point in which the straight lines meet is called the vertex of the angle. 8. When a straight line standing on another straight...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... | |
 | Andrew Bell - Euclid's Elements - 1837 - 290 pages
...contained by BD, CB, is called the angle DBG, or CBD ; but if there be only one angle at a point, it may be expressed by a letter placed at that point ; as the angle at E. It is sometimes convenient to name an angle by a small letter placed within the angle ; thus, angle... | |
 | Charles Reiner - Geometry - 1837 - 246 pages
...lines which contain the angle are called its legs. 9. Angles may either be equal or unequal. 10. If one straight line standing on another straight line makes the adjacent angles equal to each other, each of them is called a right angle. 11. All right angles are equal to each other. 12.... | |
 | John Playfair - Euclid's Elements - 1837 - 332 pages
...therefore the angle ADG is equal (8. 1.) 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 (7. def. i .) Therefore the angle GDB is a right angle : But FDB is likewise... | |
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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. 
