The side of the patio that is 12 feet is equal to 144 inches. 144 inches divided by 8 inches for each stone tells you that you can fit 18 stones along this edge. The side of the patio that is 14 feet is equal to 168 inches. 168 divided by 8 is 21, telling you that 21 stones fit along this edge. By multiplying the number of stones on each edge, you can find the total number of stones needed. 21 times 18 equals 378 stones to pave the whole patio.
