Page:First six books of the elements of Euclid 1847 Byrne.djvu/300

 266 BOOK VI. PROP. C. THEOR. fhall Y from any angle of a triangle a Jlraight line be drawn perpendi- cular to the bafe ; the rectangle contained by the fdes of the tri- angle is equal to the reSlangle contained by the perpendicular and the diameter of the circle defcribed about the triangle. From draw ■«>ii»«afa«« .. X of ^y ..-• — ; then Xthe diameter of the defcribed circle. Defcribe O (B. 4. pr. 5), draw its diameter and . and draw ^-im— • then becaufe ^ ■ >• (conft. and B. 3. pr. 31) ; ,Xl = /> (B. 3. pr. 21); .%*< is equiangular to / ^ • MHHaHMMHM l/^ and ,*. .-— .— (B. 6. pr. 16). (B. 6. pr. 4); X Q^E. D.