The elements of Euclid for the use of schools and colleges; comprising the first six books and portions of the eleventh and twelfth books; (1903)
Euclid, Todhunter, I. (Isaac), 1820-1884, ed. edt, Simson, Robert, 1687-1768, ed. edt · London; New York, Macmillan · leaf 436
that its centre isat the orthocentre of the triangle formed by the diagonals of the com-plete quadrilateral. [Use the previous Exercise and Page xxxvi, Ex. 7.] 9. If a circle be inscribed in a quadrilateral its centre lies on thestraight line joining the middle points of the three diagonals. xci… … Let AA, BB, CC meet in O, and let X, Y, Z be the intersectionsof BC and BC, of CA and CA, and of AB and AB. Since ZAB cuts the sides of the A ABO, .-. AZ. BB. OA = ZB\ BO. AA (1) [Art. 103. Since XBC cuts the sides of the A BCO, ;. BX. CC. OB = XC\ CO. BB (2) [Art. 103. Since YAC cuts the sides of…
Euclid's Elements · Geometry · Mathematics, Greek
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