A treatise on special or elementary geometry (1877)
Olney, Edward, 1827-1887, Olney, Edward, 1827-1887. Elements of trigonometry, plane and spherical · New York : Sheldon · leaf 137
1.—A circumference may be inscribed in any regularpolygon. Dem.—For, having circumscribed one about it, the equal sides become equalchords, aud hence are equally distant from the centre. If, therefore, a circle bedrawn from 0 as a centre, with Oa as a radius, it will touch every side of thepolygon… … OF THE SIDES OF POLYGONS. 117 268. An Angle at the Centre of a regular polygon is theangle included by two lines drawn from the centre to the extremitiesof a side, as FOA, AOB. 269, Co^. 3.—The angles at the centre of a regular polygon areequal each to each; and any one is equal to four right…
Geometry · Trigonometry
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