| 摘要 |
<p>A drawing instrument (20) for dividing angles into fractional components is disclosed. In the case of bisection, a simple slot (27) and equidistant points (21, 22, 23, 24) along a perpendicular bisector is disclosed. In the case of other fractions, for example trisection and quadrisection, shaped slots (33A, 34A, 35A, 33B, 34B, 35B) are provided so as to define the locus of the division point, with the point defined by scribing an arc intersecting the loci, and joining the intersection to the vertex of the angle. The instrument may also include additional features such as rulers (29, 31) protractors (28) and measured holes (30) for drawing circles and arcs.</p> |
