He moveth his tail like a cedar
His bones are as strong pieces of brass; his bones are like bars of iron.
It says "like" a cedar, not the "size" of a cedar.
Hippos have hair bristles on on their noses, ears and tails. And the shape of the bristles on their tails can have the appearance of the limbs on a lebanese cedar tree.
All the rest of the description in Job exactly fits a hippo, yet because of this one unclear part of one verse, you think this is a dinosaur. How come Job doesn't say it's dead, if it's talking about dinos?
By the way, I believe it's now thought that many large dinos, like the brontosaurus, spent their time on land, not water. The description in Job is a river animal.
It's a hippo.