Worthen, William Ezra, 1819-1897, [from old catalog] ed · New York, Appleton · leaf 34
Fig. 53. Fig. 54. angles as sides less the four right angles at the centre, the sum of the anglesof any triangle being equal to two right angles. If a line be drawn from the CONSTRUCTION OF GEOMETRICAL PROBLEMS. 17 interior point to one side, another triangle is added to the collection and tworight… … Fig. 55. Fig. 56. Fig. 57. Fig. 58. called regular polygons, and are designated by the number of their sides, aspentagons, hexagons, octagons, nonagons, decagons, etc. To describe a circle about a triangle (Fig. 59). Bisect two of the sides A B, A 0, of the triangle at E, F ; from these pointsdraw…
Mechanical drawing
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