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# Circumferential length, area online calculator

Category:

### App description

The formula for the circle:

The formula for the area of the circle is: $$S=πr2$$ or $$S=π(d/2)2$$

• π means pi
• d indicates the diameter

The circumference is: $$C = πd$$ or $$C=2πr$$

• d is the diameter of the circle
• r is the radius of the circle

### Usage example

Input data:

Input: 2

Well, this circle:

Diameter: 4

Perimeter: 12.566

Area: 12.566