 | Euclid, James Thomson - 1837 - 410 σελίδες
...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 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.... | |
 | James Thomson (LL.D.) - 1837 - 296 σελίδες
...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... | |
 | John Playfair - 1837 - 332 σελίδες
...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... | |
 | Charles Reiner - 1837 - 246 σελίδες
...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.... | |
 | Robert Simson - 1838 - 434 σελίδες
...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... | |
 | Euclides - 1838 - 264 σελίδες
...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:... | |
 | John Clark (drawing master.) - 1840 - 208 σελίδες
...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 - 1841 - 378 σελίδες
...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 σελίδες
...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 - 1842 - 332 σελίδες
...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. 
