From the above-mentioned formulae it is possible to calculate the radius. Area of a Circle Calculator. The radius is the distance between the centre and any point on the outer edge of a circle.
In the figure above drag the orange dot around and see that the radius is always constant at any point on the circle.
Enter the radius of a circle. Area of a circle p d2 2. The formula for a circle is xa 2 yb 2 r 2. A circle is the set of all points the same distance from a given point the center of the circle.