The vertex of the parabola is (1,1) and the focus is (3,1) Ends of latus rectum are (3,5) and (3,-3) Therefore, equation of the circle which has centre (1,1) and passes through (3,5) and (3,-3) is (x−1)2+(y−1)2=(3−1)2+(5−1)2 x2+y2−2x−2y+2=4+16 x2+y2−2x−2y−18=0