Exercises on Euclid and in modern geometry for the use of schools, private students, and junior university students (1881)
McDowell, James L · Cambridge, Deighton, Bell, and Co. · leaf 186
ntercepts on thetangents subtend at the centre are respectively equal to the anglessubtended by the points of contact at a point on the circumference. 192. Prove that the anharmonic ratio of four points ona circle is the same with the ratio of the rectangles under theopposite sides of the… … Join OA, OC, OB, and draw BG parallel to CB. Join AC,AC. Because CC meets the two parallels BC, CB, therefore theangles BCC and OCB are equal, but OCB and OAB in the.same segment are equal, therefore BCC equals OAB, and thereforethe quadrilateral AOCB is circumscribable by a circle. There-fore the…
Geometry
Internet Archive · Wellesley College Library · Public Domain Mark 1.0. Free to use for anything.
