 | John Playfair - Euclid's Elements - 1832 - 358 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 /• jii • • i j_ 1 / rr J f* i \ of the angles is a right angle (7. def. 1.) Therefore the aniile... | |
 | Thomas Perronet Thompson - Euclid's Elements - 1833 - 168 pages
...equivalent. But whenever the contrary is not expressed, it is always the direct angle that is meant. XXXVII. When a straight line standing on another straight...stands on the other is called a perpendicular to it ; and is also said to be at right angles to it. XXXVIII. An angle greater than a right angle, is called... | |
 | 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... | |
 | 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... | |
 | Euclid - 1835 - 540 pages
...is equal" to the angle CHG ; and they are adjacent angles ; but when a straight line standing on a straight line makes 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... | |
 | 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...stands on the other is called a perpendicular to it. 8. An obtuse angle is that which is greater than a right angle. 9. An acute angle is that which is... | |
 | 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
...equal (7. 1.) to the angle CHG, and they are adjacent angles ; but when a straight line, standing on a straight line, makes 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, James Thomson - Geometry - 1837 - 410 pages
...which 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...stands on the other is called a perpendicular to it, and is said to be at right angles to it. 9. An obtuse angle is that / which is greater than a right... | |
 | 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 a right... | |
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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. 
