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. Y5. A rightangled trianglewith equal acuteangles of 45° each. This triangle possesses the property of being divided by a per-pendicular from its right angle to its opposite side, into twotriangles of the same shape as the original whole. This prop-erty makes its construction easy. Draw this triangle
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. Y5. A rightangled trianglewith equal acuteangles of 45° each. This triangle possesses the property of being divided by a per-pendicular from its right angle to its opposite side, into twotriangles of the same shape as the original whole. This prop-erty makes its construction easy. Draw this triangle in variouspositions, and fill it with lines parallel to its longest side, Ex. 76. A triangle each of whose halves is a right angled PLANE FIGUEBS BOUNDED BY STRAIGHT LINES. 29 TTpro 3 6°—2. 36°- 90° triangle with acute angles of 36° and 54°and ||o=f. Also in the whole triangle r^/o=^. These ratiosbeing varied, while all of them are simple, the triangle is verypleasing and forms an agreeable end, or pediment, to a roof,as seen in the figure. Ex. 77. An equal sided triangle. This also, has equal anglesof 60° each, and its halves therefore haveacute angles of 30° and 60°. Draw severalsuch triangles, and fill each one of some ofthem with one or more sets of lines, parallel,or perpendicular, to some one of its sides.
Size: 2105px × 1187px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmechanicaldrawing
