Using 3.14 as Pi the area of circle is: 28.259999999999998
The area of a circle with a radius of 3 feet is: 28.27 square feet.
A circle with a radius of 3 meters has an area of 28.27 square meters.
A circle with a radius of 3 cm has an area of 28.27 square cm.
The area of a circle with radius 5 is 25 pi. Concentric circles with radius 3 and 4 have areas of 9 pi and 16 pi. The concentric circle with radius four consumes the circle with radius 3. 25 pi minus 16 pi leaves 9 pi of the circle with radius 5 left over. 16 pi is slightly over three-fifths of the circle with radius 5.
A circle has only one measure for its radius. A shape that has a "radius" of 3 in by 4 in cannot be a circle.
A circle with a radius of 3 inches has an area of 28.27 square inches.
Area = pi*radius squared
9pi
28.26
29.6088132
Since you said radius, I assume you mean Circle or Sphere. Circle: Area = Pi * radius^2 therefore, Radius = Square Root of (Area/Pi). Sphere: Area = 4/3 Pi * Radius^3 therefore, Radius = CubeRoot of (3/4 * Area/Pi)
0. There is no circle so no shaded area of a circle!