30/54 =x/1,140
30*1140= 34200
34200/54 = 633.33
ANSWER:
Estimated- 633
Make a change of coordinates:


The Jacobian for this transformation is

and has a determinant of

Note that we need to use the Jacobian in the other direction; that is, we've computed

but we need the Jacobian determinant for the reverse transformation (from

to

. To do this, notice that

we need to take the reciprocal of the Jacobian above.
The integral then changes to

The answer is 243 for the question above