A circle passes through the points (2, 3) and (4, 5). If its centre lies on the line, $$y - 4x + 3 = 0,$$ then its radius is equal to :

A line drawn through the point P(4, 7) cuts the circle x² + y² = 9 at the points A and B. Then PA⋅PB is equal to :

The two adjacent sides of a cyclic quadrilateral are 2 and 5 and the angle between them is 60^o. If the area of the quadrilateral is $$4\sqrt 3 $$, then the perimeter of the quadrilateral is :

If a point P has co-ordinates (0, $$-$$2) and Q is any point on the circle, x² + y² $$-$$ 5x $$-$$ y + 5 = 0, then the maximum value of (PQ)² is :