| Olinthus Gregory - History - 1863
...external angle A c D will be equal to the two internal opposite angles A B. " cn 2. In any triangle, **the sum of the three angles is equal to two right angles.** Cor. 1. If two angles in one triangle be equal to two angles in another : the third will also be equal... | |
| Benjamin Greenleaf - Geometry - 1863 - 320 pages
...and opposite angles CAB, ABC (Art. 34, Ax. 2). PROPOSITION XXVIII. — THEOREM. 95. In every triangle **the sum of the three angles is equal to two right angles.** Let ABC be any triangle ; A then will the sum of the angles ABC, BCA, CAB be equal to two right angles.... | |
| JAMES PYLE WICKERSHAM - 1865
...intersect each other, the opposite or vertical angles, which they form, are equal;" u ln every triangle **the sum of the three angles is equal to two right angles;"** "Every triangle is half the parallelogram which has the same base and the same altitude;" "The square... | |
| William Torrey Harris - Philosophy - 1884
...If expressed, however, it would be something like this : " We have now shown that in this triangle **the sum of the three angles is equal to two right angles** ; but that is nothing peculiar or characteristic of the triangle before us, and it is therefore true... | |
| M. Lefébure de Fourcy (Louis Etienne) - Mathematics - 1868 - 288 pages
...triangles can be formed, which will be similar to each other, but not equal. It is always understood that **the sum of the three angles is equal to two right angles.** 2. Geometry furnishes very simple constructions for determining a triangle, by means of some of its... | |
| Benjamin Greenleaf - Geometry - 1868 - 320 pages
...and opposite angles CAB, ABC (Art. 34, Ax. 2). PROPOSITION XXVIII. — THEOREM. 95. In every triangle **the sum of the three angles is equal to two right angles.** Let ABC be any triangle ; then will, the sum of the angles ABC, BCA, CAB be equal to two right angles.... | |
| Edward Brooks - Geometry - 1868 - 275 pages
...the hypothesis; hence, ABC must be greater than CAB. Therefore, etc. THEOREM XIII. In every triangle **the sum of the three angles is equal to two right angles.** c Let ABC be a triangle; then will S\ , the sum of its three angles, A, B,C, be equal to two right... | |
| Charles Davies, Adrien Marie Legendre - Geometry - 1872 - 455 pages
...equal to its alternate angle MBC (P. XX., C. 2) : hence, PROPOSITION XXV. THEOREM. In any triangle, **the sum of the three angles is equal to two right angles.** Let CBA be any triangle: then will the sum of tLe angles C, A, and B, be equal to two right angles.... | |
| Aaron Schuyler - Geometry - 1876 - 364 pages
...the angles of a given triangle. 5. Circumscribe a circle about a triangle, and prove by (153) that **the sum of the three angles is equal to two right angles.** 6. Prove by (127), (153), that the greatest angle of a triangle is opposite the greatest side ; that,... | |
| Wonders - 1877
...Earth, the Sun, and the star; when the Earth is at T', we measure the angle S T' E. In every triangle **the sum of the three angles is equal to two right angles,** — that is to say, to 180° ; then, if we make the sum of the two observed angles, STE and S T' E,... | |
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