Use the formula: diameter = circumference ÷ π
π is approximately 3.14159
If the circumference is 31.4, the diameter is about 10
If the circumference is 62.8, the diameter is about 20
Divide the circumference by 3.14159 to get the diameter
Use the formula: diameter = circumference ÷ π
π is approximately 3.14159
If the circumference is 31.4, the diameter is about 10
If the circumference is 62.8, the diameter is about 20
Divide the circumference by 3.14159 to get the diameter