An elementary treatise on modern pure geometry (1893)
Lachlan, Robert · London, New York, Macmillan and Co. · leaf 288
. Hence, by § 421, the points D, D must coincide; that is to say, the lines OD, OD intersect in a point on the line ABG. The theorem of this article may also be stated in the form : Iftwo equicross pencils have a common ray, they will also have acommon traiisversal. 425. Ex. 1. If ABC, ABC be two… … OB B Let AA, BB, CC meet in 0; and let BC, BC intersect in the point X.Then we have A {BC, 0X}=0 {BC, AX}=(i {BC, AX} = 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
Geometry
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