Concrete can be purchased by the cubic yard. how much will it cost to pour a slab 12 feet by 12 feet by 9 inches for a patio if the concrete costs $54.00 per cubic yard? since the final price is per cubic yard, i might convert everthing to yards from the beginning.

For this case, the first thing we must do is calculate the volume of the slab.
 We have then:
 V = (12) * (12) * (9 * (1/12))
 V = 108 feet ^ 3
 Making the conversion to cubic yards we have:
 V = 108 * (1/3) ^ 3
 V = 4 yd ^ 3
 Then, the cost of concrete is given by:
 C = (4) * (54)
 C = 216 $
 
 The total cost of the concrete is:
 C = 216 $