If a chord of a circle  x2+y2=25 with one extremity at   (4,3)  subtends a right angle at the centre of this circle, then the coordinates of the other extremity of this chord can be

Let P be the point  (4, 3)  and Q (h, k)   be the other extremity of the chord through P. Centre of the circle is the origin 0. Then OP  is perpendicular to OQ⇒kh×34=−1⇒kh=−43which is satisfied by  (h,k)=(−3,4)