I cannot think of the method using Menelaus Theorem , seemingly it is very difficult for us to apply it ...
Therefore also so we have
Therefore lie on a straight line .
ABCD is a cyclic quadrilateral.AB and DC when produced meet at P.again AD and BC when produced meet at R.The circumcircles of triangles BCP and CDR intersect at T. prove that P,T,R are collinear.
i have a soloution,but i want to use the Menelaus theorem or some trignometry to prove it. Is it possible to do so???