The formula for area in terms of radius is
... A = πr²
Solving this for r, we get
... A/π = r²
... r = √(A/π) . . . . . formula for the radius
For your given area, the radius is approximately
... r = √(401.92/3.14) = √128 = 8√2
... r ≈ 11.3 . . . yards
