wouldn't it be closer to 200,000 sq feet
each level was 8 feet high, except the last level which was open air, and could house the taller animals, giraffes, your favorite
so you had 5.6 floors, so let's say 6 levels.
ok 6 levels
top level was 33,750 sq feet, it's the highest point of the boat, so it would have to have been the exact 450x75, then each level slightly gets smaller, so let's assume you lose 10 percent per floor.
level 1 - 33750
level 2 - 30375
level 3 - 27337
level 4 - 24604
level 5 - 22143
level 6 - 19929
total - 158,138
now let's assume that there were above deck levels, like many ships this size
An area just for Noah and his family, then let's say two stories under neath it, which were approximately 300x50. - so another 30,000 sq feet.
Making a grand total of 188,138 sq feet
Now this is decent sized, but let's also remember that considering one of each animal, which there are millions of different species, how could he have possibly fit, let's guesstimate, 2,000,000 animals ranging from as small as a rodent to as large as an African Elephant.
It doesn't possibly make sense on that size of a boat. Even if you had one of the Navy's largest Aircraft Carriers, you couldn't fit two of every species on it.
Now onto construction. Who built the Ark? Noah?? Or did he know a boat guy, who entrusted a large team to construct it, let's say it takes 3-5 years to complete an Aircraft Carrier, with today's technology. Now that seems like a fair time to build an Ark of this size using the technology of the times in which it was supposedly constructed. And that's with a team of professional boat builders.
There is no way in hell it happened.