math
posted by Anonymous on .
A school is soundproofing a band room with insulating tiles. The room is rectangular and is 30 feet long, 40 feet wide, and 12 feet high. All four walls, the floor and the ceiling will be covered, but a window that is 10 feet long by 4 feet high will not be covered. How many square feet of tiling is needed? If each tile is 8 inches by 8 inches, how many tiles should be ordered?
thanks =)

First compute the total area.
Floor and ceiling are 30x40 = 1200 sq ft each.
Two walls are 40 x 12 = 480 sq ft (each)
The other two wall are 30 x 12 = 360 sq ft (each)
Add them up and subtract the window area of 40 sq ft.
A = 2(1200 + 480 + 360)  40 = ?
For the number of tiles needed, divide by the area of each tile, which is (2/3)^2 = 4/9 sq ft per tile. 
i get the "how many square feet of tiling is needed?" part. but each tile is given in inches and area is in feet. i don't get how to convert it to inches. please explain again...
How many square feet of tiling is needed? 4040sq ft.
How many tiles should be ordered? ... 
8 inches = 8/12 = 2/3 feet
so
8*8 = 64 in^2
or
2/3 * 2/3 = 4/9 ft^2 as Dr WLS said
You calculate the ares in square feet and divide it by 4/9 ft^2 /tile
In other words multiply the square feet needed by 9/4