 | James Thomson (LL.D.) - Arithmetic - 1837 - 296 pages
...When one straight line standing on another, makes with it two angles which are equal, each of these angles is called a RIGHT ANGLE ; and the straight line which stands on the other is said to be PERPENDICULAR, Or AT RIGHT ANGLES, tO it, or tO be a PERPENDICULAR to it. III. An OBTUSE... | |
 | 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.... | |
 | Euclides - 1838 - 264 pages
...EB; therefore the angle AFE is equal* *si to the angle BFE: but when a straight line standing upon another straight line makes the adjacent angles equal to one another, each *s Def.i. of u,,,,,, is a right« angle. there_ fore each of the angles AFE, BFE, is a right angle:... | |
 | Robert Simson - Geometry - 1838 - 434 pages
...equal (8. 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... | |
 | John Clark (drawing master.) - 1840 - 208 pages
...way. Vertical or Perpendicular Lines are those which are drawn perfectly upright. When a straight une standing on another straight line makes the adjacent angles equal to one another, then the upright une which stands on the other is called a perpendicular to it. The drawing of a perpendicular... | |
 | Euclides - Geometry - 1841 - 378 pages
...base CG; * 3. 1. 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... | |
 | Euclides - 1842 - 316 pages
...therefore the angle c HF is equal (8. 1.) to the angle c н G ; 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... | |
 | John Playfair - Euclid's Elements - 1842 - 332 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... | |
 | 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... | |
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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. 
