-ends of diameter: (-17,-9) & (-19,-9)
-- The distance between the ends of the diameter is 2,
so the radius is 1.
-- The center of the circle is the midpoint of the diameter ... (-18, -9) .
(x+18)² + (y+9)² = (1)²
-ends of diameter: (-3,11) & (3,-13)
-- The distance between the ends of the diameter is √612,
so the radius is (1/2) √612 = √153 .
-- The center of the circle is the midpoint of the diameter ... (0, -1) .
(x)² + (y+1)² = 153