Answer:
see explanation
Step-by-step explanation:
The equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k) are the coordinates of the centre and r is the radius
(5)
x² + (y - 4)² = 25 ← is in standard form
with centre = (h, k) = (0, 4) → A
(6)
here (h, k) = ( 9, - 5) and r = 1, hence
(x - 9)² + (y - (- 5))² = 1², that is
(x - 9)² + (y + 5)² = 1 ← equation of circle
which is 15!