Descriptive geometry . Fig. 115. lay off the distance 0-1; with 0 and 1 as centers, and radii 0-2and 1-2 respectively, strike arcs intersecting in point 2. Thisgives the development of the triangular face 0-1-2. With 0 and 2 as centers, radii 0-3 and 2-3 respectively,locate point 3, thus obtaining the development of the face0-2-3. In the same way obtain the faces 0-3^ and 0-4-1. The base, 1-2-3-4, of the pyramid is divided into trianglesby the diagonal 1-3, and is plotted to join one of the edgespreviously located, as 2-3. The result thus far obtained is thedevelopment of the complete pyramid.
Descriptive geometry . Fig. 115. lay off the distance 0-1; with 0 and 1 as centers, and radii 0-2and 1-2 respectively, strike arcs intersecting in point 2. Thisgives the development of the triangular face 0-1-2. With 0 and 2 as centers, radii 0-3 and 2-3 respectively,locate point 3, thus obtaining the development of the face0-2-3. In the same way obtain the faces 0-3^ and 0-4-1. The base, 1-2-3-4, of the pyramid is divided into trianglesby the diagonal 1-3, and is plotted to join one of the edgespreviously located, as 2-3. The result thus far obtained is thedevelopment of the complete pyramid. To convert it into thedevelopment of the frustum, proceed as follows : IX, § 90] INTERSECTIONS — DEVELOPMENTS 69 On 0-1, 0-2, etc., of the development, measure the truelengths of the lines 1-5, 2-6, 3-7, 4-8, and draw 5-6-7-8-5. Draw one diagonal, as 5-7, of the upper base, plot this baseby means of the two triangles thus formed, and join it prop-erly to one of the previous lines of the development. Thedevelopment
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectgeometrydescriptive
