The radius of a circle can be approximated using the expression √(A/3). A circular kiddie swimming pool has an area about 28 square feet. An inflatable full-sized circular pool has an area of about 113 square feet. How much greater is the radius of the full-sized pool than the radius of the kiddie pool? round to the nearest whole number. It says Hint: First find the radius of each pool by substituting for A in the expression. Divide by 3 before approximating square root.