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Circumference of a CircleFormula for circumference with examples The circumference of a circle is the edge or rim of a circle itself. It is the equivalent of 'perimeter' for a circle. In other words, if you took a circle and unrolled it, you would have its circumference. You can use either of the formulas below to find circumference of a circle. One formula use the radius of a circle; the other formula uses the diameter.
The rotating line on the left is an example of a circle's radius.
If the radius of a circle is 1 inch (1"), then the circumference of the circle = 2Π• 1" ≈ 6.28"
Practice Problems
Problem 1) What is the circumference of the circle below.
Problem 2) What is the circle's circumference?
Problem 3) What is the circumference of the circle pictured below?
Problem 4) What is the circumference of a circle with a radius of 5"?
Practice Problems (Medium)
Problem 5) A circle's circumference is (22Π)". What is the radius of this circle?
r = (22Π")/2Π = 11"
Problem 6) A circle's circumference is (102Π)". What is the diameter of the circle?
d = (102Π")/Π = 102" |