| Jeremiah Day - Algebra - 1814 - 303 pages
...us under the algebraic forms. Thus the proposition, that the sum of -the three angles of a triingle **is equal to two right angles, (Euc. 32. 1.) may be demonstrated, either in common** Janguage, or fey means of the signs used in algebra. Let the side AB, of the triangle ABC, (Fig. 1.)... | |
| Peter Nicholson - Building - 1823
...; but the sum of the two angles BAC, BAD, is equal to two right angles (theorem 1) ; therefore the **sum of the three angles of a triangle is equal to two right** angles. 80. COROLLARY 1. — If two angles of one triangle be equal to two angles of another triangle,... | |
| James Mitchell - Mathematics - 1823 - 576 pages
...of a triangle is less than the sum, but greater than the difference of the other two sides. 3. Tlie **sum of the three angles of a triangle is equal to two right** angles; and the external angle formed by producing one of its sides is equal to the sum of the t\vu... | |
| Ferdinand Rudolph Hassler - Geometry - 1828 - 159 pages
...of the line, which have been proved to be together, equal to two right angles; therefore, also, the **sum of the three angles of a triangle is equal to two right** angles; as was to be demonstrated. Carol. When two angles of a triangle are given, the third angle... | |
| Jeremiah Day - Algebra - 1831 - 332 pages
...XXI. APPLICATION OF ALGEBRA TO GEOMETRY.* ART. 504. It is often expedient to make use of the algebraic **notation, for expressing the relations of geometrical...by means of the signs used in Algebra. Let the side** JIB, of the triangle JJBC, (Fig. 1.) be continued to D; let the line BE be parallel toJIC; and let... | |
| Jeremiah Day - Algebra - 1832 - 332 pages
...APPLICATION OF ALGEBRA TO GEOMETRY.* •» ART. 504. It is often expedient to make use of the algebraic **notation, for expressing the relations of geometrical...triangle is equal to two right angles, (Euc. 32. 1.)** maybe demonstrated, either in common language, or by means of the signs used in Algebra. Let the side... | |
| Charles William Hackley - Trigonometry - 1838 - 307 pages
...to 47°, and the other equal to 105° 30', it will be easy to find the third angle, by recollecting **that the sum of the three angles of a triangle is equal to two right** angles (Geom. B. 1, Prop. 25,) or 180° ; therefore subtracting the sum of the two given, 47° + 105°... | |
| Jeremiah Day - Algebra - 1839 - 332 pages
...convey the same meaning. A great part of, the demonstrations in Euclid, really consist of a aeries **of equations, though they may not be presented to...means of the signs used in Algebra. Let the side'** JlB, of the triangle ABC, (Fig. 1.) be continued to D; let the line BE be parallel to AC; and let GHI... | |
| Dionysius Lardner - Curves, Plane - 1840 - 314 pages
...of the adjacent internal angle. (51.) The following consequences flow obviously from the principle, **that the sum of the three angles of a triangle is equal to** 180° : — (52.) If one angle of a triangle is right, the sum of the other two is equal to a right... | |
| John Joseph Griffin - Crystallography - 1841 - 489 pages
...in any right-angled triangle, either n or w. be given, then n, с and w are all given; because the **sum of the three angles of a triangle is equal to two right** angles. Hence: с = 90°; n = 90° — w ; and w = 90° — n. Т E.) OBLIQUE-ANGLED PLANE TRIANGLES.... | |
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