The sheet-metal worker's guide : a practical handbook for tinsmiths, coppersmiths, zincworkers, etc., comprising numerous geometrical diagrams and working patterns, with descriptive text (1888)
Crane, W. J. E. (W. J. Eden) · London : Lockwood and Son · leaf 61
49 POLYGONS. which is one side of required polygon. Mark ofi distance A b from b to r, from r to d, and d to h, round circumference. Join b f, f d, d h, and h A, and these lines will all be equals and the j9 … Fig. 44. figure will be the required regular polygon ; in this instance a pentagon. By this plan a regular polygon haying any desired number of sides can be inscribed within a given circle. If, for instance, it was required to inscribe an octagon, the student would divide the diameter into eight…
Sheet-metal work
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
