The equation of a circle is equal to: (x – h)^2<span> + (y – k)^2</span><span> = r^</span><span>2 </span> where r is the radius (x-16)^2 + y^2 = 3^2
So the radius is equal to 3. We are asked to give the diameter. Multiply the radius by 2. Then the diameter is 3*2 = 6 The correct answer is letter A. 6