PDF Radius and Diameter of Circles (A) - Free Math Worksheets by Math-Drills Radius and Diameter of Circles (J) Answers Calculate the radius and diameter of each circle. A=116.899 in2 radius = 6.1 in diameter = 12.2 in A=201.062 cm2 radius = 8.0 cm diameter = 16.0 cm C=37.071 mm radius = 5.9 mm diameter = 11.8 mm C=25.133 ft radius = 4.0 ft diameter = 8.0 ft Math-Drills.com