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 179
-178 SUPPLEMENT TO THE ELEMENTS … same EF. And because EF is perpendicular both to GH and GK,itis perpendicular (4. 2. Sup.) to the plane HGK passing throu-hthem: and EF is parallel to AB; therefere AB is at rieht angles(r. 2. Sup.) to the plane HGK. ^ For the same reason, CD islikewise it right ana;les to theplane HGK. Therefore…
Euclid's Elements · Geometry · Trigonometry
Internet Archive · Public Domain Mark 1.0. Free to use for anything.
