That's about 18 x 8.5 feet in UK terminology. I had been wondering about the size, too, as it does not like a standard size. Many thanks for the helpful demonstrations.
I want to set up a 20 x 20 like this using a vinyl tarp. I have 14 poles. I can’t find where anyone uses such a large tarp. I have ratchet straps and 16 inch steel stakes. I have climbing static rope for a ridge. Any tips? Is it likely to blow over?