Observation

The Chief Examiner reported that this question was attempted by majority of the candidates and they performed well in it. The report further stated that candidates performed better in part (a) than in part (b). Majority of the candidates were reported to show that if the square is inscribed in the circle, then its diagonal is the diameter of the circle and the mid-point of the diagonal gives the coordinate of the centre of the circle. Hence, the coordinate of the centre of the circle, (g, f), was (, ) = (4, 4). Therefore, radius of the circle = r = = . The equation of the circle was gotten using the formula (x – g)2 + (y – f)2 = r2, where f = 4, y = 4 and r2 = 13. i.e. (x – 4)2 + (y – 4)2 = 13. This simplified to x2 + y2-8x – 8y + 19 = 0.