So basically, since you know the equation and all of the dimensions, just plug in all of the numbers.
V =

r^2 h
V = 3 [the radius is diameter / 2] 4^2 * 12
V = 3 * 16 * 12
V = 48 * 12
V = 576
So there is 576 cm cubed of milk inside of the can.
(Whether it's filled to the brim, probably not.)
I hope I helped! :)