The cost of a length of fabric is proportional to the number of yards purchased. the graph shows this relationship.
what is the unit rate for cost per yard?

Unit rate means how much does it cost for 1 item for example...if you can download 2 songs for $5 how much did it cost to download 1 song...you would simply take $5 divided by 2 to get $2.50

In this case we have 5 yards of fabric for $18 so all we have to do is take $18 divided by 5 to find out how much just 1 yard costs.

so $18 divided by 5 is $3.60  so the unit rate cost per yard is $3.60 

to make sure this is correct you can check your answer like this.  If it is $3.60 for 1 yard how much would it be for 5 yards?  Multiply $3.60 and 5 if we get $18 then our answer is correct.  $3.60 x 5 does equal $18 so we were correct

What's the denominator