A circle is a collection of all points in a plane which are at a fixed distance from a fixed point. The fixed point is called the center and the fixed distance is called the radius (r).
The space occupied by a circle in a two-dimensional plane is its area. The formula for the area of a circle depends on the radius (r) or the diameter (d).
Area of a Circle (A) = πr²
Where,
π (Pi) ≈ 22/7 or 3.14
r = radius of the circle
Alternatively, since radius is half of the diameter (r = d/2):
Area (A) = π(d/2)² = (πd²) / 4