Convert 864 square inches to square feet.
1 square inch = 0.00694444444 square feet
Multiply 864 to it.
864 * 0.00694444444 = 6
Now multiply 8 to find out how many pieces of glass you need to use.
8 * 6 = 48
So you need 48 pieces of glass to make a window that is 864 square inches.
