Mr. rameriz is buying square stones to cover his patio. the patio measures 7.5 feet by 9 deer. each stone is 6 inches on a side. if mr. rameriz buys 275 stones, are there enough stones to cover the patio

The first thing we must do in this case is to calculate the area of the patio.
 We have then that:
 A = (7.5) * (9) = 67.5 feet ^ 2.
 Then, we calculate the area of each stone:
 Ap = (6) * (6) = 36in ^ 2
 We make the conversion to feet:
 Ap = (36) (in ^ 2) * (1/12) ^ 2 (foot / inches) ^ 2
 Ap = 0.25 feet ^ 2
 Finally we have that the area covered by all the stones is:
 (0.25) * (275) = 68.75 feet ^ 2
 We observed that:
 68.75 feet ^ 2> 67.5 feet ^ 2
 
 there are enough stones to cover the patio
 68.75 feet ^ 2> 67.5 feet ^ 2

The answer is the third choice