When a straight line set up on a straight line makes the adjacent angles equal to one another, each of the equal angles is right, and the straight line standing on the other is called a perpendicular to that on which it stands. Introduction and books 1,2 - Page 181by Euclid, Sir Thomas Little Heath, Johan Ludvig Heiberg - 1908Full view - About this book
| Elias Loomis - Geometry - 1871 - 58 pages
...angle ECD is the difiei ence between the two angles BCD, BCE. 10. When a straight line, meeting another **straight line makes the adjacent angles equal to one another, each of** them is called a right angle, and the straight line which meets the other is called a perpendicular... | |
| Henry Major - Student teachers - 1873
...therefore the angle CHF is equal to 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... | |
| William Alexander Myers, Jean Etienne Montucla - Circle-squaring - 1873 - 164 pages
...concentric circles ; *that is, having a common center, as at F. 14. When a straight line standing on another **straight line makes the adjacent angles equal to one another, each of the** angles is a right angle, and the straight line which stands on the other is called a perpendicular... | |
| WILLIAM ALEXANDER MYERS - 1874
...concentric circles ; that is, having a common center, as at F. 14. When a straight line standing on another **straight line makes the adjacent angles equal to one another, each of the** angles is a right angle, and the straight line which stands on the other is called a perpendicular... | |
| Euclides - 1874
...meet together, but are not in the same straight line. 10. 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... | |
| Euclides - 1874
...1. The angle AFE is equal to the angle BFE (I. 8) ; but when a straight line standing upon another **straight line, makes the adjacent angles equal to one another, each of** them is a right angle (I. Def. 10) ; therefore 2. Each of the angles AFE, BFE is a right angle ; wherefore... | |
| John Clement Primrose Aldous - Trigonometry - 1874 - 71 pages
...one well-known angle by which angles may be measured. DBF. When one straight line standing on another **straight line makes the adjacent angles equal to one another, each of** these angles is called a Bight Angle. Now all right angles are equal to one another. So that any angle... | |
| Francis Cuthbertson (geometer.) - 1874
...and.-. AE is =BE; (i. i) ( 14 ) RIGHT ANGLES. DEFINITION. When one straight line, standing on 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 said to be perpendicular... | |
| Henry Lewis (M.A.) - 1875
...it is, perhaps, a little too difficult for beginners: — When a straight line standing on another **straight line makes the adjacent angles equal to one another, each of** these angles is called a right angle. An acute angle is less than a right angle, as ABD, DEE. An obtuse... | |
| Edward Atkins - 1876
...to the angle CHG (I. 8), and they are adjacent angles. But 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... | |
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