b) So lies in the circumference of the circle. P (1, 3) is the centre of a circle and a point Q (7, 11) is any point in its circumference. Find the diameter of the circle. Does another point (-5, 10) lie in the circumference of the circle?

b) So lies in the circumference of the circle. P (1, 3) is the centre of a circle and a point Q (7, 11) is any point in its circumference. Find the diameter of the circle. Does another point (-5, 10) lie in the circumference of the circle?