Answer
Maximum value of $r$ can be approximately 70 yards.
Work Step by Step
The minimum value of $r$ can be $0$ because the radius cannot be negative and the maximum value of $r$ at $x=0$ is:
$r_{0y.}=\dfrac{440-(2)(0)}{2 (3.14)}\approx 70.06$y.
Thus, the maximum value of $r$ can be approximately 70 yards.
