Given diameter = 8 ⇒ Radius = 4 Also diameters equations: y + 2x - 5 = 0 ...(i) 2y + 3x - 8 = 0 ...(ii) Substracting 2 × (i) from (ii) -x + 2 = 0 x = 2 Putting back in (i) y + 2 × 2 - 5 = 0 y = 1 So center is (2, 1) and radius 4 The equation of circle: (x−2)2+(y−1)2=42(x−2)2+(y−1)2=42 ⇒x2+4−4x+y2+1−2y=16x2+4−4x+y2+1−2y=16 ⇒x2+y2−4x−2y−11=0 x2+y2−4x−2y−11=0