Note-Book on Practical Solid or Descriptive Geometry; Containing Problems with Help for Solutions - Tapa blanda

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Book may have numerous typos, missing text, images, or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1880. Excerpt: ... II. COMBINATIONS AND GROUPS OF SOLIDS. 1. A prism, with bases equilateral triangles, is placed with one face on the horizontal plane. On the centre of it rests a brick, 9 by 3 by 4-5 inches, with one of the short edges of a large face touching the ground, with the centre of thai face touching the highest edge of the prism and with the face itself inclined 450 Horizontal edge of prism 9 inches. The side of the equilateral base to be determined from the question. Scale . Draw plan and elevation, and a second elevation taking the vertical plane at 300 with any horizontal edge of the prism. Commence with an elevation so placed that both bases of the prism coincide. To do this, draw first the elevation of the brick, which will be simply a rectangular parallelogram. Through the lowest corner take xy making the required angle with the line that represents the face inclined 450, and make the centre of this line the vertex of the triangle, recollecting that the elevation of the base of that triangle must according to the conditions be in xy, the ground line. The work for the plan is simple. The second elevation will be determined by taking the new ground line 300 with any horizontal edge of the prism, and working to it. z. Instead of the prism take a cylinder with brick touching it and otherwise disposed as above. The base of the cylinder to be determined from the question; i.e. so that the horizontal bisecting line of the face of the brick may be in contact with the cylinder. 3. A block, 3 in. square and 1 in. thick, is pierced by a hexagonal prism 1 in. side and 4 in. long. Axis of prism passing through centres of square faces of block and projecting equally on each side. Two faces of the prism to be parallel to two narrow faces of the block. (a) Plan when the block stands on one of its na...