An elementary treatise on modern pure geometry (1893)
Lachlan, Robert · London, New York, Macmillan and Co. · leaf 288
= A {BC, OX].Hence by § 424, AB, AC will intersect AB, AC, in points which arecollinear with X. Ex. 2. If ABCD be any tetraatigm, and if E, F, G \>e respectively theG … 272 EXAMPLES. points of intersection of AB, CD ; AC, BD; AD, BC; show that the pencilG {EF, AB] is harmonic (§ 141). Let GF cut AB in H, and CD in A. Then we have, G{EF, AB}=F{EH, AB} ^F{EK, CD} = G{EF, BA}. Therefore, by § 417, the pencil G {EF, AB} is harmonic. Ex. 3. If {ABC}, {ABC} be two…
Geometry
Internet Archive · Cornell University Library · Public Domain Mark 1.0. Free to use for anything.
