area of the circle
Kapitoly: Area of the square, Area of the rectangle, Area of the circle, Area of the trapezoid, Area of the parallelogram, Area of the rhombus, Area of a regular n-gon, The surface of a sphere, The surface of a cube, The surface of a cuboid, Surface of a cylinder, The surface of a needle
By the volume of a circle, we mean the size of the area that a circle (or circle, as the case may be) occupies. Let's denote the radius by r. Then the area of the circle, denoted by S, is equal to
$$\Large S = \pi \cdot r^2$$
The sign π represents pi, the Ludolph number. Its abbreviated value is 3.14, but we usually leave multiples of Pi in the result. The following circle has radius r = 3, so the area of the circle will be equal to
$$\Large S = \pi \cdot 3^2 = 9\pi\approx28{,}26$$
