If one of the diameters of the curve x² + y² $$-$$ 4x $$-$$ 6y + 9 = 0 is a chord of a circle with centre (1, 1), the radius of this circle is

The equation of a line parallel to the line 3x + 4y = 0 and touching the circle x² + y² = 9 in the first quadrant, is

The locus of the mid-points of chords of the circle x² + y² = 1, which subtends a right angle at the origin, is