Answer: 3.499 now 3.079 is correct
see the figure below to better understand the problem
we have that

<h2>The answer is 357.0 feet</h2>

which follows from the usual change of coordinates via

and Jacobian determinant

Swap the order, so that the integral is

and now let

, so that

. Now, you have
-84 is a real number, a rational number, and an integer