12.
Answer: 30.25π
11π = circumference
diameter * π = circumference
diameter = 11
radius = 5.5
Area = 5.5 * 5.5 * π
Area = 30.25π
13.
Answer: 52π
Area = radius * radius * pi
Area = 676π
Radius = 26
Diameter = 2 * radius
Diameter = 52
Circumference = 52π
14.
Answer: 38π
Area = radius * radius * pi
Area = 1134.11
Radius ≈ 19
Diameter = 38
Circumference = 38π
15.
Answer: 72.25π
Circumference = diameter * π
53.41 = diameter * π
Diameter ≈ 17
Radius = 8.5
Area = radius * radius * π
Area = 72.25π
