Shush fhoncizbizxoabcobad
The Jacobian for this transformation is

with determinant
, hence the area element becomes

Then the integral becomes

where
is the unit circle,

so that

Now you could evaluate the integral as-is, but it's really much easier to do if we convert to polar coordinates.

Then

Answer:
66ft
Step-by-step explanation:
c=pixD
c=pix21
c=65.9...=66ft