Answer:
9 units
Center is at (5, 0)
Step-by-step explanation:
The radius of the circle is equal to the square root of 81
= ±9
Since the radius of a circle must be positive the answer is 9 units.
The center of the circle is at (5, 0)
The correct answer is A = 2 x pi x r x h. So basically the answer is C. Hope I helped! :)