Curtains of the Mishkan

The curtains of the Mishkan that form the middle roof are made up of 11 strips sown together. Each one has a length of 30 amos (cubits) and a width of 4 amos [Shemos (Exodus) 26:2].

Question: What is the total area of the curtains? 

Answer: 30 x 4 x 11 = 1,320 square amos (square cubits)