 | Thomas J. Foster - Coal mines and mining - 1891 - 444 pages
...greater side is opposite the greater angle, and the greater angle is opposite the greater side. 7. In an isosceles triangle the angles opposite the equal sides are equal. 8. In any triangle the sum of the three angles is equal to two right angles, or 180°. 9. If two angles... | |
 | Seth Thayer Stewart - Geometry - 1891 - 428 pages
...XIV. 5§1. Theorem Many propositions fire equally true with spherical and plane triangles ; thus, I. In an isosceles triangle, the angles opposite the equal sides are equal. II. If two angles of a triangle are equal, the sides opposite are equal. III. If a triangle is equilateral,... | |
 | George Bruce Halsted - Geometry - 1896 - 208 pages
...second. Proof. For the angle opposite the second cannot be the greater, nor can they be equal. 380. Theorem. In an isosceles triangle the angles opposite the equal sides are equal. Proof. The bisector of the angle between the equal sides is a symmetry axis for those sides and their... | |
 | 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... | |
 | Education - 1893 - 568 pages
...angle of one are equal, respectively, to two sides and the included angle of the other. 13. Theorem: i. In an isosceles triangle, the angles opposite the equal sides are equal. 2. If two angles of a triangle are equal, the opposite sides are equal, and the triangle is isosceles.... | |
 | William Chauvenet - 1893 - 340 pages
...the one are respectively equal to a side and the two adjacent angles of the other. PROPOSITION VIII. In an isosceles triangle the angles opposite the equal sides are equal. Corollary. The straight line bisecting the vertical angle of an isosceles triangle bisects the base,... | |
 | 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
...angles and a side of one are equal respectively to two angles and the homologous side of the other. 147. Theorem. In an isosceles triangle the angles opposite the equal sides are equal. 148. Corollary. An equilateral triangle is equiangular, and each angle is equal to 60 degrees. 149.... | |
 | 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... | |
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In an isosceles triangle the angles opposite the equal sides are equal. 
