a=area
p=pi
r=radius
sqr(a/p)=r
If yo have the area of the circle, the square is irrelevant. Radius = sqrt(Area/pi)
The answer depends on what information you are given.
By using the other information supplied about the circle to calculate either its radius (from which its area can be calculated) or its area (if the circle is similar to another with a given area and some ratio between the two circle is given):If the diameter is given: radius = diameter ÷ 2If the circumference is given: radius = circumference ÷ 2πIf the circle is similar to another circle which has a given area, and the length ratio is given; square the length ratio to get the area ratio and apply to the given area.
Divide the area by pi and then square root it this will give the radius of the circle.
Area = pi*radius2 So, radius = sqrt(area/pi)
Half the square root of the square radius equals the circle radius.
If the circumference or diameter is given then you can find the radius or simply measure the distance from the centre of the circle to the circumference.
A = pi x radius squared where pi = 3.14
A = pi x radius2
If 'R' is the radius of the circle, then-- area of the circle is [ pi R2]-- perimeter of the circle is [ 2 pi R ]
Area of a circle = pi x radius squared, so to get the radius, divide the Area by pi (3.14159), and then find the square root of that
-- Take the formula for the area of the circle in terms of the radius . . . A = (pi) R2-- Solve that formula for 'R'. You'll then have a formula for the radius in terms of the area,which is exactly what you're looking for.