Bill bought a piece of cloth that was 30 inches wide and 12 feet long. if the cloth cost $6 per square yard, then how much did it cost him

Let's figure out how many square yards you have by first converting all of the measurements into yards:
30 inches x( 1 yard/36 inches) = 30/36 yd = 5/6 yd
12 feet x (1 yard/3 feet) = 4 yards.

Now multiply length x width:
5/6 x 4 = 20/6 or 3 1/3 square yards.

Finally, multiply unit price by square yards:
$6 per sq yd x 3 1/3 sq yd = $20 cost

There is no association.