M represents the month because the value is decreasing every month.
Hope this helps :)
Evaluate
at
:

Compute the line element
:

Simplifying the integrand, we have

Then the line integral evaluates to

Answer:
v = l * w * h
v = 3/4 * 1/2 * 1/4 = <u>3/32 or 0.09375</u>
(5.6)(1.8) the answer is 10.08