Books Books 1 - 10 of 180 on Thus the proposition, that the sum of the three angles of a triangle is equal to.... Thus the proposition, that the sum of the three angles of a triangle is equal to two right angles, (Euc. An Introduction to Algebra: Being the First Part of a Course of Mathematics ... - Page 290
by Jeremiah Day - 1847 - 332 pages ## An Introduction to Algebra: Being the First Part of a Course of Mathematics ...

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.)... ## The new practical builder, and workman's companion, Volume 2

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,... ## Dictionary of the Mathematical and Physical Sciences, According to the ...

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... ## Elements of the Geometry of Planes and Solids: With Four Plates

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... ## An Introduction to Algebra: Being the First Part of a Course of Mathematics ...

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... ## An Introduction to Algebra: Being the First Part of a Course of Mathematics ...

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... ## Elements of Trigonometry, Plane and Spherical: Adapted to the Present State ...

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°... ## An Introduction to Algebra: Being the First Part of a Course of Mathematics ...

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... ## A Treatise on Geometry and Its Application in the Arts

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... 