Text-book of Euclid's elements for the use of schools : books I - VI and XI (1900)
Hall, H. S. (Henry Sinclair), 1848-1934, Stevens, F. H. (Frederick Haller), 1853-1933 · MacMillan : London · leaf 447
BD,.*. AB is perp. to the plane containing BE, BD, namely theplane XY ; XL 4. and since BF is in this plane,.-. AB is also perp. to BF. XI. Def. 1. But AB is perp. to BC ; Hyp. .*. the ^8 ABF, ABC, which are in the same plane AF, areboth rt. angles; which is impossible. .*. BC is not outside the… … Let the st. lines AB, CD be perp. to the plane XY,Then shall AB and CD be par1.* Let AB and CD meet the plane XY at B and D.Join BD;and in the plane XY draw DE perp. to BD, making DEequal to AB. Join BE, AE, AD. Then since AB is perp. to the plane XY, Hyp... AB is also perp. to BD and BE, which…
Geometry · Mathematics
Internet Archive · UBC Library · Public Domain Mark 1.0. Free to use for anything.
