 | Thomas Keith - Navigation - 1810 - 478 pages
...likewise equiangular, and the contrary. (I) COROLLARY III. A line drawn from the vertex of an isosceles triangle to the middle of the base, is perpendicular to, the base. For the two sides FB and BC are equal to the two sides FA and AC, and the angle FBC is equal to the... | |
 | Adrien Marie Legendre - Geometry - 1819 - 574 pages
...the angle BAD = DAC, and the angle BDA = ADC. Consequently the two last are right angles ; therefore, the arc drawn from the vertex of an isosceles spherical...triangle to the middle of the base, is perpendicular lo this base, and divides the angle opposite into two equal parts. THEOREM. Fig. 332. 485. In any spherical... | |
 | Adrien Marie Legendre - Geometry - 1822 - 394 pages
...demonstration proves the angle BAD=DAC, and the angle BDA=ADC. Hence the two 172 last are right angles ; hence the arc drawn from the vertex of an isosceles spherical triangle to the middle of the base, is at right angles to that base, and bisects the opposite angle. PROPOSITION XVI. THEOREM. In a spherical... | |
 | Adrien Marie Legendre, John Farrar - Geometry - 1825 - 294 pages
...angle BAD — DAC, and the angle BDA = ADC. Consequently the two last are right angles ; therefore, the arc drawn from the vertex of an isosceles spherical...triangle to the middle of the base, is perpendicular to this base, and divides the angle opposite into two equal parts. I s~ THEOREM. I ' 485. In any spherical... | |
 | Adrien Marie Legendre - 1825 - 570 pages
...DAC, and the angle BDA = ADC. Consequently the two last arc right angles ; therefore, the arc draxn from the vertex of an isosceles spherical triangle to the middle of iht base, is perpendicular to this base, and divides the angle opposite into two equal parts. THEOREM.... | |
 | Adrien Marie Legendre - Geometry - 1825 - 276 pages
...the angle BAD - DAC, and the angle BDA = ADC. Consequently the two last are right angles ; therefore, the arc drawn from the vertex of an isosceles spherical triangle to ihe middle of the base, is perpendicular to this base, and divides the angle opposite into two equal... | |
 | Adrien Marie Legendre, John Farrar - Geometry - 1825 - 280 pages
...the angle BAD - DAC, and the angle BDA = ADC. Consequently the two last are right angles; therefore, the arc drawn from the vertex of an isosceles spherical triangle to ihe middle of the base, is perpendicular to this base, and divides the angle opposite into two equal... | |
 | Thomas Keith - Navigation - 1826 - 504 pages
...likewise equiangular, and the contrary. (I) COROLLARY III. A line drawn from the vertex of an isosceles triangle to the middle of the base, is perpendicular to the base. For the two sides FB and вс are equal to the two sides FA and AC, and the angle FBC is equal to the... | |
 | Dionysius Lardner - Plane trigonometry - 1828 - 434 pages
...sides, they will be symmetrically equal, and the proposition has been already proved. (152.) Cor. Hence the arc drawn from the vertex of an isosceles spherical triangle to the point of bisection of the base, bisects the vertical angle, and is perpendicular to the base. * In... | |
 | James Hayward - Geometry - 1829 - 228 pages
...angles opposite to the equal sides, are equal. 2. A straight line drawn from the summit of the isosceles triangle to the middle of the base, is perpendicular to the base, and bisects the angle ivhose vertex is at the summit. Fi%. 27. 46. If the triangle had been equilateral (fig. 27), that is,... | |
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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. 
