Elements of geometry : containing the first six books of Euclid, with a supplement on the quadrature of the circle, and the geometry of solids : to which are added, Elements of plane and spherical geometry (1826)
Playfair, John, 1748-1819, Euclid · Philadelphia : Marot & Walter · leaf 184
d let CE be the common sec-tion of the planes DE, CK; take anypoint F in CE, from which dra***FG in the plane DE at right angles to CE: And because AB is perpen-dicular to the plane CK, therefore d g a hit is also perpendicular to everystraight line meeting it in that plane(l. def. 2. Sup.); and…
Euclid's Elements · Geometry · Trigonometry
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