 | Elias Loomis - Conic sections - 1858 - 256 pages
...the angle ECD is the difference 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... | |
 | Euclides - 1860 - 288 pages
...point. Thus, angle DBC may be called angle n ; and ABD, angle m. 11. When a straight line standing on another straight line makes the adjacent angles equal...and the straight line which stands on the other is called a perpendicular to it. 12. The two adjacent angles which one straight line makes with another... | |
 | Isaac Todhunter - 1860 - 318 pages
...meet together, but are not in the same straight line. And when a straight line standing on another makes the adjacent angles equal to one another, each of the angles is called a right angle. A right angle is divided into 90 equal parts called degrees, a degree is divided into 60 equal parts... | |
 | Popular educator - 1860 - 536 pages
...angle CHF (I. 4) to the angle CBO ; 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 them is a right angle, and the straight line which stands upon the other is called a perpendicular... | |
 | Robert Potts - Geometry, Plane - 1860 - 380 pages
...therefore the angle A FE is equal to the angle BFE; (l. 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 ; (l. def. 10.) therefore each of the angles AFE, BFE, is a right angle : wherefore... | |
 | William Schofield Binns - 1861 - 238 pages
...one another, meeting or cutting each other in a point, as c (10) " When a straight line standing on another straight line makes the adjacent angles equal...and the straight line which stands on the other is called a perpendicular to it." The angles AB c, ABD, are right angles. Obs. 1. Because DB is in the... | |
 | Janes Boddely Keene - 1861 - 104 pages
...1. 10. Angles are of three kinds. Fig. 2. a. The Right Angle. — If one straight line standing on another straight line makes the adjacent angles equal to one another, each is .called a right angle, and the line standing on the other is said to be perpendicular to it. b.... | |
 | Euclides - 1862 - 140 pages
...equal to the angle ECF; (I. 8.) And they are adjacent angles. 5. But when a straight line, standing on another straight line, makes the adjacent angles equal...another, each of the angles is called a right angle; (def. 10.) 6. Therefore each of the angles DCF, ECF, is a right angle. Conclusion. — Therefore from... | |
 | Euclides - 1862 - 172 pages
...therefore 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 anele ;' therefore each of the angles AFE, BFE, is a right angle; wherefore the straight... | |
 | Euclides - 1863 - 122 pages
...expressed by a letter placed at that point; as the angle at E. X. 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 ; and the straight line which stands on tbo other is called a... | |
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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. 
