Circle Calculator
Know one of a circle's radius, diameter, circumference or area? Get all the others.
Area
78.53981634
- Radius
- 5
- Diameter
- 10
- Circumference
- 31.41592654
Show the work
Square the radius
r to the power of 2 = r × r
5 × 5 = 25
Area
A = π × r to the power of 2
π × 25 = 78.53981634
How it works
d = 2r; C = 2πr; A = πr²
Questions
- How does the circle calculator work?
- d = 2r; C = 2πr; A = πr².
- What do I need to enter?
- I know the, Value, Units. Optional fields can be left blank.
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