math
posted by jan .
Sam wants to tile the roof of his shed with square tiles that are 4 inches square. His roof is 12 feet by 12 feet. How many tiles does he need?

A tile 4 inches square is 4 inches by 4 inches for an area of 16 square inches
or 1/3 ft by 1/3 ft for an area of 1/9 square feet
area of roof = 144 square feet
number of tiles = 144/(1/9) = 1296
or
number of square inches in 144 square feet
= 144(144) = 20736
number of tiles = 20736/16 = 1296