How big is the size 87x54 for a tapestry?

7 1/4 feet by 4 1/2 feet. Close to the size of a 4x8 sheet of plywood. It is very big.

I can't believe how many people can't do simple math. First of all what country do you live in? I'm guessing America or else you would have learned in school how to figure this out on your own. I'm assuming you mean 87 inches by 54 inches? It's going to be totally different if it's centimeters. There are 12 inches in a foot, if you didn't know that so you divide 87 by 12 and you divide 54 by 12 to give you an idea of how many feet it is. By doing simple math it's 7 feet e inches by 4 feet 6 inches. Does that give you an idea of how big it is? If not then buy yourself a yard stick and measure it out.

This reminds me of a poem I heard as a kid; "Poor little Ida, sitting on a fence. Trying to make a dollar out of 97 cents."