| Charles Hutton - Mathematics - 1812 - 620 pages
...which some property is asserted, and the truth of it required to be proved. Thus, when it is said that, 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. — A set or collection of such... | |
| Charles Hutton - Mathematics - 1822 - 616 pages
...some property is asserted, and the truth of it required to be .proved. Thus, when it is said that, 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. — A set or collection of such... | |
| American Institute of Instruction - Education - 1835 - 318 pages
...work, this author has pursued a different method in regard to parallel lines, by first proving that the sum of the three angles of any triangle is equal to two right angles ; but the demonstration is tedious and difficult for beginners, and is therefore rarely understood.... | |
| Adrien Marie Legendre - Geometry - 1836 - 394 pages
...equal to two right angles. PROPOSITION XXV. THEOREM. In every triangle the sum of the three angles is equal to two right angles. Let ABC be any triangle : then will the an- R glc C + A + B be equal to two right angles. For, produce the side CA towards D, and... | |
| Benjamin Peirce - Geometry - 1837 - 216 pages
...perpendicular to its base, divides it, by art. 57, into the two equal triangles ABC and ABG. 64. Theorem. The sum of the three angles of any triangle is equal to two right angles. Demonstration. Let ABC (fig. 36) be the given triangle. Produce AC to D, and draw CE parallel to AB.... | |
| Elias Loomis - Algebra - 1846 - 380 pages
...statement of some property, the truth of which is required to be proved. Thus when it is said that 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. (8.) A. problem is a question requiring... | |
| Elias Loomis - Algebra - 1846 - 376 pages
...statement of some property, the truth of which is required to be proved. Thus when it is said that 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. (8.) A problem is a question requiring... | |
| Benjamin Peirce - Geometry - 1847 - 204 pages
...perpendicular to its base, divides it, by § 57, into the two equal triangles ABC and ABG. 65. Theorem. The sum of the three angles of any triangle is equal to two right angles. Proof. Let ABC (fig. 36) be the given triangle. Produce AC to D, and draw CE parallel to AB. The angles... | |
| Charles Davies - Trigonometry - 1849 - 372 pages
...equal to two right angles. PROPOSITION XXV. THEOREM. In every triangle the sum of the three angles is equal to two right angles. Let ABC be any triangle : then will the angle C + A + B be equal to two right angles. For, produce the side CA towards D, and at the... | |
| Charles Davies - Geometry - 1850 - 238 pages
...is equal to the outward angle CBD (Ax. 1). THEOREM XVII. In any triangle the sum of the three angles is equal to two right angles. Let ABC be any triangle : then will the sum of the three angles C A+B+C=two right angles. For, let the side AB be produced to D. Then,... | |
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