Mr Nelson is making a car lard fort in the shape of a square pyramid for his son. The gas of the square pyramid has a length of 6.3 feet.the height of each triangular face is 5.85 feet.
The entire exterior of the square pyramid, including the base, will be covered with felt. Each roll of felt is 6 feet long and 3 feet wide. Mr Nelson needs to purchase ___ rolls of felt so that the exterior of the square pyramid can be completely covered.
Type the correct answer in the box. Use numerals instead of words.