 | Seth Thayer Stewart - Geometry - 1893 - 262 pages
...SPHERICAL TRIANGLES. 5§1. Many propositions are equally true~with spherical and plane triangles ; thus, I. In an isosceles triangle, the angles opposite the equal sides are equal. Draw arc of great О from vertex to middle of base. The two Дs have respectively = sides (hyp. and... | |
 | Webster Wells - Geometry - 1894 - 400 pages
...conclusions is contrary to the hypothesis that BC is greater than EF. PROPOSITION XXX. THEOREM. 91. In an isosceles triangle, the angles opposite the equal sides are equal. Let AC and BC be the equal sides of the isosceles triangle ABC. To prove ZA = Z B. Draw CD perpendicular... | |
 | George Albert Wentworth, George Anthony Hill - Geometry - 1894 - 150 pages
...HARVARD COLLEGE, June, 1891. In solving problems use fur w the approximate value 3\. 1. Prove that in an isosceles triangle the angles opposite the equal sides are equal to each other. The area of a certain isosceles triangle is 50 square feet and each of its equal sides... | |
 | Adelia Roberts Hornbrook - Geometry - 1895 - 224 pages
...that the equal sides shall coincide, and show the truth of the following theorem : PRINCIPLE 17. — In an isosceles triangle the angles opposite the equal sides are equal. 13. In the isosceles triangle ABC the angle BAC is 70°. How many degrees are there in each exterior... | |
 | George Albert Wentworth - Mathematics - 1896 - 68 pages
...third side of the first triangle is greater than the angle opposite the third side of the second. 154. In an isosceles triangle the angles opposite the equal sides are equal. 155. Cor. An equilateral triangle is equiangular, and each angle contains 60°. 156. If two angles... | |
 | Electrical engineering - 1897 - 672 pages
...to the base extended. Thus, in Figs. 33 and C 34, BD is the altitude FIG. 33. of the triangles ABC. In an isosceles triangle, the angles opposite the equal sides are equal. Thus, in Fig. 35, AB = BC; hence, angle C= angle A. In any isosceles triangle, if a perpendicular be... | |
 | George Washington Hull - Geometry - 1897 - 408 pages
...contrary to the hypothesis that AB is greater than DE. Hence Z C> Z F. QKD PROPOSITION XXIV. THEOREM. 63. In an isosceles triangle, the angles opposite the equal sides are equal. D Given—The triangle ABC, isosceles, with AC= EC. To Prove— Z A — Z B. Dem.—Draw CD perpendicular... | |
 | James Howard Gore - Geometry - 1898 - 232 pages
...obtuse-angled triangle the sum of the acute angles is less than a right angle. PROPOSITION XVII. THEOREM. 93. In an isosceles triangle the angles opposite the equal...are equal. Let ABC be an isosceles triangle in which AC and BC are the equal sides. To prove that Z A = Z B. Draw CD perpendicular to AB. Then the triangles... | |
 | Webster Wells - Geometry - 1898 - 284 pages
...hypothesi£ that BC is > EF. Then, if ZA can be neither equal to ZD, nor < ZD, ZA> PROP. XXX. THEOREM. 93. In an isosceles triangle, the angles opposite the equal sides are equal. D Given AC and BC the equal sides of isosceles A ABC. To Prove ZA = Z B. Proof. Draw line CD _L AB.... | |
 | International Correspondence Schools - Surveying - 1898 - 518 pages
...to the base produced. Thus, in Figs. 32 and33, CBD is the altitude of the triangles AB C. PlC. 47. In an isosceles triangle, the angles opposite the equal sides are equal. Thus, in Fig. 34, AB = BC; hence, angle C = angle A. Therefore, if two angles of any triangle are equal,... | |
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In an isosceles triangle, the angles opposite the equal sides are equal. 
