Circumference Calculator
Enter any one of the value (A, C, d, r) to know the other remaining terms along with their formulas.
Circumference of a Circle Calculator
This circumference calculator is used to calculate the total distance around a circular object. Our tool helps you to find the circumference, radius, diameter, and area of any circle by entering just one known value.
If you're working on circle-related geometry problems, this article helps you to make things simple.
Keep going to learn more:
◉ What is the circumference (definition & formula);
◉ How to calculate circumference using radius or diameter;
◉ How to convert circumference into diameter, radius, or area;
What is the Circumference of a Circle?
The circumference of a circle is the distance around its outer edge. In simple words, it is similar to perimeter, but the word perimeter is used for shapes with straight sides, while circumference is used for circles.
? To draw a circle on the Cartesian plane, you might need this equation of a circle calculator.
Circumference Formula:
The circumference can be calculated using different formulas depending on whether the radius, diameter, or area is known.
➤ Using Radius:
When the radius is known, you can calculate the circumference by multiplying the radius by 2 and then by π (pi).
Circumference = 2πr
➤ Using Diameter:
If the diameter is given, the circumference can be found by multiplying it directly by π (pi).
Circumference = πd
➤ Using Area:
The area is the amount of space inside a shape. Instead of using the circumference calculator, it can be calculated manually by the formula:
Circumference = 2 × √ π × A
Where:
- r = Radius
- d = Diameter
- π ≈ 3.14159
How to Calculate the Circumference of a Circle?
Using Radius
- Measure the radius of a circle.
- Multiply the radius by 2.
- Multiply the result by π (pi).
Example:
Suppose a circle has a radius of 7 cm. What is the circumference?
Solution:
First, multiply the radius by 2: 2 × 7 = 14
Now multiply by π (≈ 3.14): 14 × 3.14 = 43.96 cm
Answer: The circumference of the circle is 43.96 cm.
Using Diameter
- Measure the diameter of the circle.
- Multiply the diameter by π (pi).
Example:
Suppose a circle has a diameter of 10 cm.
Solution:
Multiply the diameter by π (≈ 3.14): 10 × 3.14 = 31.4 cm
Answer: The circumference of the circle is 31.4 cm.
? As you known the circumference of a circle calculator is used to find circle measurements. But to find the unknown side measurements of right-angle triangles, use our Pythagorean theorem calculator.
How to Convert Circumference into Diameter?
The circumference, which can also be known as the perimeter of a circle, can be converted into a diameter, radius, or area by just dividing the circumference. So, the conversion can be done by using the formulas given below:
Diameter (D) = C ÷ π
Radius (R) = C ÷ (2π)
Area (A) = C² ÷ (4π)
C / D = 2πR / 2R = π
? If you want to explore how circumference connects with other measurements, check out our circumference to diameter calculator and circumcenter calculator.
FAQs:
Is the circumference 3.14 times the diameter?
Yes, the circumference of a circle is about 3.14 times greater than its diameter. The exact ratio is a mathematical constant known as pi (π) and can be represented by the equation C = πd.
How to calculate the radius from the circumference?
We need to follow the steps given below to find out the radius when the circumference is known:
- Formula used to find the radius: R = C ÷ (2π)
- Dividing the circumference by π to find the diameter
- Divide the diameter by 2 to find the radius
Who calculated the circumference of the Earth first?
Eratosthenes was a Greek scholar who was the first person to accurately calculate the Earth's circumference around 240 B.C., using a difference in shadow length between two Egyptian cities (Alexandria and Syene) and the distance separation.
What is the circumference of circle with diameter of 30 cm?
Follow the steps below for a diameter of 30cm;
- Apply the circumference formula C = πd
- Substitute the values in formula C=π×30
- Circumference is approximately 94.2 cm
What is the circumference of a 60-inch diameter circle?
To find the circumference of a circle, multiply the diameter by π. For a 60-inch diameter, the circumference is 188.4 inches. Instead of calculating it manually, you can use this free circumference calculator to get an instant and accurate results.
References:
Wikipedia Circumference of a circle: Circle, Relationship with π, Ellipse
SplashLearn (2024) Circumference to Diameter: Conversion, Formula, Meaning, Example.
Study.com (2014) Circumference of a Circle | Formula & Calculation.
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