 | 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.... | |
 | Aaron Schuyler - Geometry - 1876 - 384 pages
...adjacent angle of ACD ; A and B are the opposite interior angles. 52. Proposition XVI.— Theorem. The sum of the three angles of any triangle is equal to tiro right angles. Let ABC be a triangle. Then the B sum of its angles is equal to two right /\ angles.... | |
 | Humanities - 1877 - 626 pages
...Further, since any triangle can be resolved into two right-angled triangles, it follows immediately that the sum of the three angles of any triangle is equal to two right angles. If, then, we accept the evidence of Pamphila as satisfactory, we are forced to the conclusion that... | |
 | William Chauvenet - Geometry - 1879 - 380 pages
...+ AC •we subtract AB, we shall have BC — AB<AC, otAC> BC—AB. PROPOSITION XVIII—THEOREM. 68. The sum of the three angles of any triangle is equal to two righl angles. Let ABC be any triangle; then, the sum of its three angles, A, B and C, is equal to two... | |
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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. 
