Elements of plane and solid free-hand geometrical drawing, with lettering; and some elements of geometrical ornamental design, including the principals of harmonic angular ratios, etcIn three parts ..for draughtsmen and artisans; and teachers and students of industrial and mechanical drawing . Ex. 72. A four pointed star, requiring two lines at rightangles to each other, and the equal bisecting lines of those Ex. 73. A gate. ISTote that an angle of 24° is four-fifteenthsof a right angle. I r~\ Ex. 74. An arch, giving practice in parallels, equal distances(each side of the arch, and th
Elements of plane and solid free-hand geometrical drawing, with lettering; and some elements of geometrical ornamental design, including the principals of harmonic angular ratios, etcIn three parts ..for draughtsmen and artisans; and teachers and students of industrial and mechanical drawing . Ex. 72. A four pointed star, requiring two lines at rightangles to each other, and the equal bisecting lines of those Ex. 73. A gate. ISTote that an angle of 24° is four-fifteenthsof a right angle. I r~\ Ex. 74. An arch, giving practice in parallels, equal distances(each side of the arch, and the heights at the ends) and arcs, ofvarious sizes, and parts of a circle. CHAPTER Yl. PLANE FIGURES BOUNDED BY STRAIGHT LINES. Prvncvples. K plane figure is a portion of a flat surface, bounded bylinesWlien bounded by straight lines, it is called ?k jpolygon. Polygons are of various names, depending on their numberof sides. A Triangle has the least possible number of sides, viz., has also three angles, and when one of these is a right angle,the triangle is called right angled. A Quadrilateral, or quadrangle, has four sides, and both the angles and sides are equal, the figure is a square,and its angles are all equal. When the angles are right angles,but only the opposite sides are equal, the figure is called a rec-tangle. A Pejitagon is a figure of five sides. In a regular pentagonthe sides
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmechanicaldrawing
