I'm gonna have to go with 9x9.
that you are unlikely to get wet in the tent. basically, at 3000mm the tent is rainproof but not water proof. so if it rains heavily, you will be fine, as long as you don't put extensive pressure on the tent walls. but if you submerge your tent in water, it will not be able to keep the water out. the higher the mm, the more water proof the tent will be. 3000mm is very good.
It depends on how tall the tent is.
Tent.
12 comfortably but can squeeze 14 if it is a frame tent
A tent...
yes the point of tarp is to keep the tent off the floor it needs tarp
George Washington Army Tent refers to the tent that campers put up when they go to the wild. This is in reference to the tent that George Washington did build during the American Revolutionary War.
You do not necessarily need a mat under a tent. If your tent has its own 'floor', sometimes having a mat under it is a good idea to prevent it from being torn by sharp objects on the bare ground or inside the tent. If it has no floor, and your tent is on sand or gravel, a mat is nice to have because it makes the floor cleaner and more comfortable for bare feet, and may reduce the chance of insect bites.
contubernium(tent group)
Is this in inches? If so the tent is the size of a very small apartment.
The ground floor
There are various products available to waterproof a tent and its floor. Check out these sites for ideas and options: http://www.trek7.com/ AND http://boyslife.org/outdoors/askgearguy/2725/waterproofing-a-tent/ AND http://hubpages.com/hub/Tent-Waterproofing-Tips Puchase a waterproofing spray. This is usually sold in a can in a camping goods store. Follow the directions carefully. Make sure to apply thoroughly to the tent floor. Also make sure to mae sure the tent material is adequately covered with the product, following the directions of the product you purchased.
"Expensive". It truly is ridiculous how expensive they can be. Any ware from $1500 to $3500 for your slandered size 10x12. that price sometimes does not in clued the floor.
The smallest Roman army unit was the contuberium, which was an eight man tent unit.
to the best of my knowledge the only thing on an previously "untreated" tent would be the tarpaulin floor material. The fabric that makes up the b"body" of the tent isn't truly waterproof when "untreated"( a waterproofing solution). The fabric will shed water but will wick through on contact from the opposite side. So if a tent isn't treated with a waterproofing product the only part inherently waterproof would be the floor.
Size, capacity, materials, style and weather resistance are all important things to consider when making your purchase. Size: First and foremost you'll want to consider the size and dimensions of the tent you're looking at.
If you know how to find the area of a triangle do the same thing and you will get the same answer.