 | Ferdinand Rudolph Hassler - Trigonometry - 1826 - 208 pages
...sine of its supplement, not only in magnitude, but also in sign ; and because the sum of all the three angles of a plane triangle is equal to two right angles, the sine of any one of the angles is equal to the sine of the sum of the two others. Calling d the perpendicular... | |
 | Stephen Chase - Geometry - 1847 - 28 pages
...connected with it are among the first that interest the young mind, and the interest need not flag, so long as new truths remain to be considered ; in other words,...study Geometry, paying him wages, as for any other labor. At length, however, he told his pupil, that he could no longer bear the expense, and must forego... | |
 | JAHANN AUGUST GRUNERT - 1847 - 540 pages
...8. Geometrie. Elements of Geometry, with a New Demonstration, not depending on any Postulate, that the Sum of the Angles of a Plane Triangle is equal to Two Right Angles. By JD 1847. 8. 3 sh. Theorie des parallèles, démontrée d'une manière simple et rigoureuse, sans... | |
 | Technology - 1847 - 648 pages
...sewed, T1LEMENTS OF GEOMETRY: with а Кет •*-' Demonstration, not depending on any Postulate, that the Sum of the Angles of a Plane Triangle is equal to Two Right Angles. By JD London: Longman, Brown, Green, anil Longmans. CONTENTS OF THIS NUMBER, Description of Mr. Craddock's... | |
 | Ludwig Adolph Sohncke - 1854 - 422 pages
...ementi , unier A. Elements of Geometry., with a new demonstration, not depending on any postulate, tbat the sum of the angles of a plane triangle is equal to two right angles. By JD ln-8. London 1847. Longman. 3 sh. Elington, T., s.Euclids Elements of Geometry , unter C. Dupin... | |
 | William John Macquorn Rankine - Civil engineering - 1863 - 810 pages
...Triangles. — All these formulae are deduced from the two following principles : — The sum of the three angles of a plane triangle is equal to two right angles. The sides of a plane triangle are proportional to the sines of the opposite angles. When the computations... | |
 | Henry Nathan Wheeler - Plane trigonometry - 1876 - 130 pages
...before, positive. § 21. The following principles of Plane Geometry must be borne in mind : — , a. The sum of the angles of a plane triangle is equal to 180°. 6. The sum of the two acute angles of a plane right triangle is equal to 90°. Either of these... | |
 | Henry Nathan Wheeler - Trigonometry - 1876 - 254 pages
...before, positive. § 21. The following principles of Plane Geometry must be borne in mind : — a. The sum of the angles of a plane triangle is equal to 180°. b. The sum of the two acute angles of a plane right triangle is equal to 90°. Either of these... | |
 | Friedrich Paulsen - First philosophy - 1898 - 518 pages
...propositions of mathematics are absolutely universal and necessary. No observation can shake or change the proposition that the sum of the angles of a plane triangle is equal to two right angles ; it is implied in the notions themselves as their logically necessary consequence. On the other hand,... | |
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He had demonstrated, unaided by any book or teacher, the proposition, that the sum of the angles of a plane triangle is equal to two right angles. 
