[The Saucepan Man]

Originally Posted by obloquy

Because a chasm is narrow, meaning it is much longer than it is wide, we know the room must have been more than 50 feet wide.

A chasm does not necessarily have to be narrow. The dictionary definition that I have simply refers to a chasm as a "deep fissure". But, even accepting that the chasm was narrow, it does not follow that the length of the chasm was delineated by the width of the chamber. The chasm might well (and probably did) continue beyond the bounds of the chamber. It is entirely feasible, therefore, that the width of the chamber was equal to or less than the width of the chasm.

Say the chamber was 40 foot wide (and the double line of towering pillars is not incompatible with this, particularly if its height was greater than its width) and the Balrog therefore had a 40 foot wingspan, that would, according to the ratio you have given, make the Balrog 14 foot tall, which is the assumption of the remainder of the argument.

Although I cannot resist making one further point:

Originally Posted by obloquy

In fact, there are numerous example of leaping Balrogs, especially in the passages on the duel with Glorfindel, which would be awkward for a giant Balrog to do.

Not if it had wings ...

Originally Posted by obloquy

I can't deny that Tolkien most probably envisioned the Balrog scene with literal wings. It's definitely how I imagined it when I first read LotR.

This is all that is required. If one imagines it with wings then, in the absence of any firm evidence to the contrary, one is quite entitled to continue imagining it as such.