Circle Area and Circumference Calculator
Calculate the diameter·circumference·area of a sphere using radius.
Input
The example value has been entered. Check it immediately or change the value.
Input is processed in the browser. Refreshing returns a sample value.
Result
Check or change the value using the example value result.
Fractional results are displayed up to 12 digits of precision. Please unify units in the input values.
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Calculation·conversion criteria
Calculate the area and circumference of a sphere using radius.
Input example
Radius 2: area ≈ 12.5663706144
If the radius is 3, the area is 9π and the perimeter is 6π. If 3 is entered as the diameter, it should be changed to 1.5; otherwise, the area is calculated 4 times larger.
How to use
- Use the entered example value or change the radius item.
- Click Verify result and check the following result.
- Result can be copied if needed.
Frequently Asked Questions
If the radius is doubled, how does the area and perimeter change?
The circumference is 2 times the radius, and the area is 4 times the radius squared. The result’s circumference is in length units, and the area is in square units.
Calculation criteria and reference materials
The calculation formula and scope of this tool are disclosed in the above description. Examples can be checked by substituting input values into the formula or following the specified string and calendar handling rules.
Verification of calculation criteria: · Calculation·verification principles · Report errors