David –
What do you mean?
Fine but Brooklyn in area is greater than twelve mil by twelve mil. Rav Moshe follows the Shulchan Aruch and requires a daily shishim ribo (see 4:88 regarding the beaches). Consequentially, we still fall short of 3 million.
How do you know that you still fall short of 3 million (using the aforementioned criteria) in a 12×12 mil area subset?