 | 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... | |
 | Alpheus Crosby - Geometry - 1847 - 190 pages
...aABC + aACB = AmL? M. .-. ACD 4- ACS xa BAG + ABC -j- ACS ? 20. a. ACD *w BAC + ABC ? XXII. A COR. Any exterior angle of a triangle is equal to the sum of the two interior opposite angles. It is of course greater than either singly. Draw CE ]| BA, and prove... | |
 | 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... | |
 | 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,... | |
 | 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 - 436 pages
...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. a Let BC H be an exterior angle of the triangle ABC. We are to prove Z BCH= Z. A + ZB Z. B С 11+ Z... | |
 | George Anthony Hill - Geometry - 1880 - 348 pages
...53) ? Therefore, m = a -\- c (Axiom I.). That is, — Theorem. — An exterior angle of Fiff- **• a triangle is equal to the sum of the two opposite interior angles. Exercises.- — 1. Find the exterior angle of a triangle if the opposite interior angles are 38° 35'... | |
 | George Albert Wentworth - Geometry, Modern - 1881 - 266 pages
...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. л— — Let BC H be an exterior angle of the triangle ABC. We are to prove ZB СH = ZA + Z B. ZB... | |
 | Edward Olney - Geometry - 1883 - 352 pages
...angle formed by any side with its adjacent side produced, as CBD, Fig. 116. PROPOSITION IV. Theorem.— Any exterior angle of a triangle is equal to the sum of the two interior non-adjacent angles. DEMONSTRATION. Let ABC be a triangle, and CBD be an exterior... | |
 | George Albert Wentworth - 1884 - 264 pages
...31. Corollary II. The sum of the acute angles of a right triangle is equal to 90°. 32. Theorem. An exterior angle of a triangle is equal to the sum of the two opposite interior angles. 33. Theorem. The sum of the angles of a quadrilateral is equal to 360°. 34. Theorem. The sum of the... | |
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Any exterior angle of a triangle is equal to the sum of the two opposite interior angles. 
