Kitap 1
20
OF the figures which the geometers call sxh/mata there are two kinds, plane and solid. These the Greeks themselves call respectively e)pi/pedos and stereo/s. A plane figure is one that has all its lines in two dimensions only, breadth and length; for example, triangles and squares, which are drawn on a flat surface without height. We have a solid figure, when its several lines do not produce merely length and breadth in a plane, but are raised so as to produce height also; such are in general the triangular columns which they call pyramids, or those which are bounded on all sides by squares, such as the Greeks call ku/boi, See Euclid, Elementa I, Definitions, 20, cubs autem est aequaliter aequalis aequaliter, sive qui tribus aequalibus numeris comprehenditur. and we quadrantalia. For the ku/bos is a figure which is square on all its sides, like the dice, says Marcus Varro, Fr. p. 350, Bipont. with which we play on a gaming-board, for which reason the dice themselves are called ku/boi Similarly in numbers too the term ku/bos is used, when every factor Euclid, l. c., 17, "ubi autem tres numeri inter se multiplicantes numerum aliquem efficiunt, numerus inde ortus soliduss" (= ku/bos) est, latera autem eius numeri inter se multiplicantes. consisting of the same number is equally resolved into the cube number itself, That is, is an equal factor in the cube number. as is the case when three is taken three times and the resulting number itself is then trebled.
