 | Horatio Nelson Robinson - Geometry - 1860 - 470 pages
...the theorem ; the sum of the angles of any parallelogram it eoual tc four right angles. THEOREM XI. The sum of the three angles of any triangle is equal to two right angles. Let AB C be a triangle, and through its vertex C / draw a line parallel to the b\e/a base AB, and produce... | |
 | Elias Loomis - Algebra - 1864 - 386 pages
...is the statement of some property, the truth of which is required to be proved. Thus the principle that the sum of the three angles of any triangle is equal to two right angles, is a theorem, N the truth of which is demonstrated by Geometry. (8.) A problem is a question requiring... | |
 | Horatio Nelson Robinson - Geometry - 1868 - 276 pages
...the theorem ; the sum of the angles of any parallelogram it toual k four right angles. THEOREM XI. The sum of the three angles of any triangle is equal to two right angles. Let AB O be a triangle, and through its vertex C draw a line parallel to the base AB, and produce the... | |
 | William Chauvenet - Geometry - 1871 - 380 pages
...AC we subtract AB, we shall have BC — AB <AC,orAC> BC — AB. PROPOSITION XVIII.— THEOREM. 68. The sum of the three angles of any triangle is equal to two right angles. Let ABC be any triangle ; then, the sum of its three angles, A, B and C, is equal to two right angles.... | |
 | William Chauvenet - Mathematics - 1872 - 382 pages
...XI \j \ve subtract AB, we shall have BC - AB < AC, orAOBC — AB. PROPOSITION XVIII.— THEOREM. 68. The sum of the three angles of any triangle is equal to two right angles. Let ABC be any triangle ; then, the sum of its three angles, A, B and C, is equal to two right angles.... | |
 | Education - 1873 - 698 pages
...the following series, V, %. ¿£, I. All this can be demonstrated as satisfactorily as we can prove that the sum of the three angles of any triangle is equal to two right angles. But we cannot tell what is the exact area of any one of these circles. There exist other curious relations... | |
 | American Association for the Advancement of Science - Science - 1875 - 390 pages
...forces. A NEW DEMONSTRATION OF AN OLD THEOREM IN GEOMETRY. By" BENJ. S. HEDRICK, of Washington, DC "THE sum of the three angles of any triangle is equal to two right angles." In any triangle, ABC, from either of the angles as C, a line CD, may be drawn to the opposite side.... | |
 | Horatio Nelson Robinson - 1875 - 288 pages
...with AB, and from B draw the line BC, making with BA an angle equal to 84°. Produce AB to D. Because the sum of the three angles of any triangle is equal to two right angles, the angle C of the triangle ABC, must be 0= 180° - (32° + 84°) = 64. The exterior angle CBD=180°—... | |
 | American Association for the Advancement of Science - Science - 1875 - 962 pages
...forces. A NEW DEMONSTRATION OF AN OLD THEOREM IN GEOMETRY. By BENJ. S. HEDRICK, of Washington, DC " THE sum of the three angles of any triangle is equal to two right angles." In any triangle, ABC, from either of the angles as C, a line CD, may be drawn to the opposite side.... | |
 | American Association for the Advancement of Science - Science - 1875 - 392 pages
...forces. A NEW DEMONSTRATION OF AN OLD THEOREM IN GEOMETRY. By BENJ. S. HEDRICK, of Washington, DC . "TiiE sum of the three angles of any triangle is equal to two right angles." In any triangle, ABC, from either of the angles as C, a line CD, may be drawn to the opposite side.... | |
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The sum of the three angles of any triangle is equal to two right angles, this is a Theorem, the truth of which is demonstrated by Geometry. 
