Smith, David Eugene, 1860-1944 · Boston, New York [etc.] Ginn and Company · leaf 323
7V5) ^(V5+3) 12 v Some interest is added to the study of polyhedrons bycalling attention to their occurrence in nature, in theform of crystals. The computation of the surfaces andvolumes of these forms offers an opportunity for applying 312 THE TEACHING OF GEOMETRY the rules of mensuration, and the… … They show how the cube is modified by having itscorners cut off. A cube may be inscribed in an octahe-dron, its vertices being at the centers of the faces ofthe octahedron. If we think of the cube as expanding,the faces of the octahedron will cut off the corners of thecube as seen in the first…
Geometry
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![An illustration from Divina proportione : opera a tutti glingegni perspicaci e curiosi necessaria oue ciascun studioso di philosophia: prospettiua pictura sculptura: architectura: musica: e altre mathematice: suavissima: sotile: e admirabile doctrina consequira: e delecterassi: co[n] varie questione de secretissima scientia (1509)](https://img.insideoutlibrary.com/img/200/ia-divinaproportion00paci-222-423.webp)
