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...Chapter somegeometryproblems ax and by are angle bisectors of triangle abc with x on bc y ac suppose ab a determine the angles b if cz is external bisector c z exten sion ba show that solution togetherwitha we have half therefore tan consider square abcd sidelength an equilateral xcd in interior let mbethemidpointofab d t m since dax isosceles adx xam right am mx q at bisects theorem tm xm fromtheright applying law tangents to xcy which cy xy now thismeans...