 | William Pease - Geometry - 1843 - 80 pages
...that which is formed on the surface of a sphere, by the intersection of two of its great circles. X. When a straight line standing on another straight...stands on the other is called a perpendicular to it. Beginners are apt to suppose that a perpendicular, must be a vertical, or plumb line, which it need... | |
 | Philip Kelland - Algebra - 1843 - 168 pages
...centre is the angular point, as trigonometers often make it. 7. When a straight line standing on another makes the adjacent angles equal to one another, each...stands on the other is called a perpendicular to it. By looking over the propositions of Euclid's first Book it will be seen that the only definitions which... | |
 | Scottish school-book assoc - 1845 - 444 pages
...» only one angle at the point, as at E, it may be called simply the »ngle at E, PLANE GEOMETRY. 9. When a straight line standing on another straight...each of the angles is called a right angle; and the strnight line which stands on the other is called a perpendicular to it. 10. An obtuse angle is that... | |
 | Euclid, James Thomson - Geometry - 1845 - 382 pages
...line standing on another makes the adjacent angles equal, each of the angles is called a right ample; and the straight line which 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 angle. 10.... | |
 | Euclides - 1845 - 546 pages
...be only one angle at a point, it may be expressed by the letter at that point; as the angle at /.'. When a straight line standing on another straight line makes the adjacent angles equal to each other, each of these angles is called a right angle ; and the straight line which stands on the... | |
 | Euclid - Geometry - 1845 - 218 pages
...§ II is Def. 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... | |
 | Euclides - 1846 - 292 pages
...EF— therefore (1. 8) the angle DCF is equal to the angle ECF ; and they are adjacent angles : But, when a straight line, standing on another straight...the adjacent angles equal to one another, each of these angles is called a right angle (Def. 10) ; therefore each of the angles DCF, ECF is a right angle... | |
 | Great Britain. Admiralty - Geometry - 1846 - 128 pages
...only one angle at a point, it may be expressed by a letter placed at that point, as the angle at E. X. angle; and the straight line which stands on the other, is called a perpendicular to it. XI. An obtuse angle is that which is greater than a right angle. XII. An acute angle is that which... | |
 | Great Britain. Admiralty - Geometry - 1846 - 128 pages
...The extremities of a superficies are lines. VII. A plane superficies is that in which any two «r C angle; and the straight line which stands on the other, is called a perpendicular to it. XI. An obtuse angle is that which is greater than a right angle. XII. An acute angle is that which... | |
 | Euclid, John Playfair - Euclid's Elements - 1846 - 334 pages
...equal (8. 1.) to the angle CHG ; and they are adjacent angles ; now 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... | |
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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. 
