The correct answer to this item is letter D. To get the surface area of a circle, one must use the formula r squared multiply by pi. Since the radius is not given, divide the diameter by 2. So, 55 ft divided by 2 is 27.5 and this will be the radius.

Next, multiply 27.5 by 27.5 and the product will be 756.25. The value of pi is 3.14 where we multiply 756.25 to it. We will get the answer of 2,374.625. Usually, the answer is rounded off to retain a whole number; the final answer will be 2,375 square feet. Whether the radius or the diameter is given and memorize the value of pi, you can easily solve for the surface area of circles.

2,375.835 sq ft math constant: area of a circle formula, diameter squared x 0.7854 (0.7854 is 1/4th of pi, 3.1416/4=0.7854) 55x55x0.7854=2,375.835 sq ft