In this case, we'll have to carry out several steps to find the solution.
Step 01:
Data:
(x - 4)² + y² = 16
Step 02:
polar form:
x = r cos (θ)
y = r sin (θ)
(r cos (θ) - 4 )² + (r sin (θ))² = 16
(r cos θ - 4)² + r² sin² θ = 16
r (r - 8 cos (θ)) = 0
r = 8 cos θ
The answer is:
r = 8 cos θ