Circle area
To find the area of a circle, there is a formula that is best remembered:
S=πr2 – it is the product of pi and the square of the radius.
Since the radius is closely related to the diameter and circumference, by simple substitutions, the area of the circle can also be calculated through the diameter 
or circumference 
.
Diameter – it is the doubled radius, so substituting it into the formula instead of the latter, it needs to be divided back by two.
The circumference is the doubled product of the radius and the number π: P=2πr, by the reverse method, we find that the radius equals the circumference divided by its multiplier.
These online calculators are designed for calculating the area of a circle. The calculation is based on the aforementioned geometric formulas, where π is considered a constant rounded to the 15th decimal place. Definition: A circle is a part of a plane enclosed by a circumference, and it is a convex shape. 
The result of the calculator's work is also rounded to the same digit. To use the circle area calculator, you only need to enter the value of the radius, diameter, or circumference of the circle. For the calculator, the units of measurement for the radius do not matter – the result is calculated in absolute terms. That is, if the radius value is given, for example, in centimeters, then the calculated area of the circle should also be interpreted as presented in square centimeters. |