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
28.26
29.6088132
A circle with a radius of 3 meters has an area of 28.27 square meters.
The area of a circle with a radius of 3 feet is: 28.27 square feet.
A circle with a radius of 3 cm has an area of 28.27 square cm.
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
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!
It's half of the area of the whole circle...
A≈28.27cm2