 ADC ; the last two are therefore right angles ; hence the arc drawn from the vertex of an isosceles spherical triangle to the middle of the base, is perpendicular to the base, and bisects the vertical angle.  The Elements of Geometry - Page 334by Webster Wells - 1886 - 371 pagesFull view - About this book
 | Benjamin Greenleaf - Geometry - 1863 - 504 pages
...to DAC, and the angle BDA is equal to ADC ; the last two are therefore right angles ; hence the arc drawn from the vertex of an isosceles spherical triangle to the middle of the base, is perpendicular to the base, and bisects the vertical angle. PROPOSITION XVI. — THEOREM.... | |
 | Benjamin Greenleaf - Geometry - 1868 - 340 pages
...to DAC, and the angle BDA is equal to ADC ; the last two are therefore right angles ; hence the arc drawn from the vertex of an isosceles spherical triangle to the middle of the base, is perpendicular to the base, and bisects the vertical angle. PROPOSITION XVI. — THEOREM.... | |
 | William Chauvenet - Geometry - 1871 - 380 pages
...angle BAD equal to the angle CAD, and the angle ADB equal to the adjacent angle ADC; therefore, the arc drawn from the vertex of an isosceles spherical triangle to the middle of the base is perpendicular to the base and also bisects the vertical angle. 80. Scholium. This proposition... | |
 | Elias Loomis - Geometry - 1871 - 302 pages
...angle ADB to the angle ADC ; therefore each of the last two angles is a right angle. Hence the arc drawn from the vertex of an isosceles spherical triangle, to the middle of the base -t perpendicular to the base, and bisects the vertical aigle. GEOMETRY PROPOSITION XVH.... | |
 | William Chauvenet - Geometry - 1872 - 382 pages
...angle BAD equal to the angle CAD, and the angle ADB equal to the adjacent angle ADC; therefore, the arc drawn from the vertex of an isosceles spherical triangle to the middle of the base is perpendicular to the base and also bisects the vertical angle. 80. Scholium. This proposition... | |
 | Adrien Marie Legendre - Geometry - 1874 - 500 pages
...ADB is equal to AD C, and the angle DAB is equal to DA C ; that is, if an arc of a great circle be drawn from the vertex of an isosceles spherical triangle to the middle of its base, it will be perpendicular to the base, and will bisect the vertical angle of the triangle.... | |
 | Aaron Schuyler - Geometry - 1876 - 384 pages
...equungular ; (?) hence, B and C are equal, since they an opposite the common side AD. . 463. Corollaries. 1. The arc of a great circle drawn from the vertex of...spherical triangle to the middle point of the base bisects the vertical angle, is perpendicular to the base, and divides the triangle into two symmetrical... | |
 | George Albert Wentworth - Geometry - 1877 - 416 pages
...sphere arc mutually equiangular). .-.¿B-=-¿C, (sinet they are homologous A of symmetrical &). QED 746. COROLLARY. The arc of a great circle drawn from the...vertex of an isosceles spherical triangle to the middle of the base bisects the vertical angle, is perpendicular to the base, and divides the triangle into... | |
 | George Albert Wentworth - Geometry - 1877 - 416 pages
...equiangular). .-.ZB = ZC, (since they are homologous A of symmetrical A). QED 746. COROLLARY. The are of a great circle drawn from the vertex of an isosceles spherical triangle to the middle of the base bisects the vertical angle, is perpendicular to the base, and divides the triangle into... | |
 | Groombridge and sons - 1878 - 138 pages
...in writing out their Answers.] 1. Prove that, in an isosceles triangle, the line joining the vertex to the middle point of the base, is perpendicular to the base, and bisects the angle at the vertex. 2. Two isosceles triangles stand on the same base, either on the same or on opposite... | |
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