An elementary treatise on modern pure geometry (1893)
Lachlan, Robert · London, New York, Macmillan and Co. · leaf 293
. Hence the points X, Y, Z are collinear. Ex. 2. If a, h, c, d, e, f be six tangents to a circle, prove that the linesjoining the pairs of points ah, de; he, ef; cd, fa; are concurrent. (Brian-chons theorem.) Ex. 3. Any straight line is cut in involution by a circle, and the oppositeconnectors of… … Let ABCD be a tetrastigm inscribed in a circle, and let a straight line bedrawn, cutting the circle in P, P, and the pairs of connectors of the tetra-stigm in the points X, X; Y, Y; Z, Z. Join AP, AP, CP, CP. Then we have A {PP, XZ} = A {PP, BD}; and C{PP, XZ} = C{PP, DE}=^G{PP, BD}. But by § 428,…
Geometry
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