Geometry

Circle Area & Circumference

Enter the radius or the diameter of a circle. You can keep the answer exact, written as a multiple of π, or round it to a decimal.

InputsA = πr²

Measurement givenValueUnitAnswer form

Step-by-step

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Fill in the fields and press Solve. The full method will appear here, one numbered step at a time.

Explained with worked examples in the Formula Library.