# Area of a Circle Calculator

The area of a circle calculator helps you to calculate the area of a circle with the diameter, radius and circumference of a circle.

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## Area of a Circle

The area of a circle is defined as the amount of space it takes to completely surround the circle. It is calculated by the equation A = πr2, where A is the area, r is the radius, and π is the constant pi (approximately 3.14159). The formula can be rearranged to find the radius of a circle if you know its area. Area of a circle = π times the square of the radius.

## Area of a Circle formula

Given the radius of the circle, the area is the radius squared times pi. Given pi is 3.14159, it would be written as area=r2*pi

◉ Area of a circle with radius.

Area of circle = π(r)² = π(radius)²

◉ Area of a circle calculator with a diameter

Area of circle = π(D/2)² = π(dimater/2)²

◉ Area of a circle with a circumference

Area of circle = C²/4π = circumference²/4π

## How to solve the area of a circle

Example.1:-The radius of a circle is 10 cm, find its area.

Answer:- Area = πr² = 22/7 * (10)² = 314.15 cm².

Example.2:-The circumference of a circle is 20 cm, find its area.

Answer:- Circumference of circle = 2πr = 20 cm

Area = πr² = π * (10/ π)² = 100/π = 31.83 cm².

Example.3:-The diameter of a circle is 20cm, find its area.