 | John Narrien - Geodesy - 1845 - 484 pages
...the angle s' EH is equal to twice the angle AFB or OAF, produce FB to K, and FA to M : then because the exterior angle of a triangle is equal to the sum of the interior and opposite angles (Euc. 32. 1.), the angle ABK = BAF + AFB; whence 2 ABK = 2 BAF +2... | |
 | Anna Cabot Lowell - Geometry - 1846 - 206 pages
...other. 134. The exterior angle of a triangle, that is, the angve made by producing one of the sides of a triangle, is equal to the sum of the two opposite interior angles, (fig. 88.) Angle ACD = angle ABC + angle CAB. Dem. ACD + ACB = 2 RA; ABC + CAB -f ACB = 2 RA; therefore... | |
 | George Clinton Whitlock - Mathematics - 1848 - 338 pages
...Triangle is equal to a right angle Cor. 8. The external angle formed by producing one of (94) the sides of a triangle, is equal to the sum of the two opposite internal angles. Let a, b, c, be the three angles of any triangle, and с adjacent to the external... | |
 | Alexander Ingram - 1851 - 202 pages
...the angle ACB. Supposing that APB = P, APC =p; CP = d; AC = C\^ - VP L, and BC = R are known. Since the exterior angle of a triangle is equal to the sum of the two interior and opposite angles ; then the angle AJB = P + IBP, and AIB is also equal to C + CAP... | |
 | James Pryde - Navigation - 1867 - 506 pages
...of incidence, their complements are also equal ; hence L BAD = L SAF, and L DBC = L GBA. But since the exterior angle of a triangle is equal to the sum of the two interior angles, L. EBC = L ВАС + L. ACB = L. BAD + L DAG + L ACB = L. BAD + L SAF + L ACB... | |
 | Richard Wormell - Geometry, Modern - 1868 - 286 pages
...It follows that in a right-angled triangle two angles are acute, and their sum is a rightangle. 127. The exterior angle of a triangle is equal to the sum of the interior and opposite angles. F'g- 1°3- When the side of a triangle is produced, the new angle... | |
 | Michigan. Department of Public Instruction - Education - 1893 - 564 pages
...done in the simplest manner you can conceive. GEOMETRY. Demonstrate the following propositions: 1. Any exterior angle of a triangle is equal to the sum of the two opposite interior angles. 2. If the squares of the sides of a quadrilateral are together equivalent to the squares of the diagonals,... | |
 | Richard Wormell - Geometry, Plane - 1870 - 304 pages
...rightangles, these two straight lines are parallel (§ 100). Consequences of the above properties. 20. The exterior angle of a triangle is equal to the sum of the interior and opposite angles ; and the three angles of a triangle are together equal to two right-angles... | |
 | Chicago (Ill.). Board of Education - Elementary schools - 1872 - 130 pages
...right angles. a=db=ec=c d-{-e+c=a + b + c, or a flat angle, or two right angles. THEOREM II.—The exterior angle of a triangle is equal to the sum of the two opposite interior angles. g + d= 2 right angles. c+d+e=^2 right angles. g+d=c+d+c. In the following figures, mark and name angles.... | |
 | George Albert Wentworth - Geometry - 1877 - 426 pages
...is one third of two right angles, or two thirds of one right angle. PROPOSITION XXII. THEOREM. 105. The exterior angle of a triangle is equal to the sum of the two opposite interior angles. С Let EС H Ъе an. exterior angle of the triangle ABС. We are to prove Z. B С H = ZA + Z B. Z... | |
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An exterior angle of a triangle is equal to the sum of the two opposite interior angles. 
