At Orange County Choppers, Paul Teutul Junior needs to make a circular metal disk with area $875 \ in^2.$

The radius of such a disk is inches.

To keep Paul Senior from blowing a gasket, Paul Junior must deviate from the ideal area of the disk, which is $875 \ in^2$, by less than $\pm 3 \ in^2.$ How close to the ideal radius must the Flowjet (the machine that cuts the disk) be to maintain tranquility at OCC?

Answer = inches.

In terms of the $\epsilon, \delta$ definition of $\displaystyle \lim_{x \to a} f(x) = L$, let $x$ be the actual radius of the disk and $f(x)$ the actual area of the disk.
What is the formula for the function $f(x)$?
What is the number $a$?
What is the number $L$?
What value of $\epsilon$ is given?
What is the corresponding value of $\delta$?