Rectangle area
Geometry
How to calculate circle area
The radius is the distance from the centre to the edge. Square the radius and multiply by pi to get the area. A radius of two gives an area of about 12.566 square units.
Formula
π × radius²
Worked example
- Radius
- 5
Applying the formula to these values gives 78.5398163397 square units.
What should I check?
If you know the diameter, divide it by two first. A radius in metres gives an area in square metres.
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