The pipeline has a rate of 1 inch to one foot. 20 yards are equivalent to 20*3 = 60 ft. To find the drop (x) we can use the next proportion:
[tex]\frac{1\text{ in}}{x\text{ in}}=\frac{20\text{ yards}}{60\text{ yards}}[/tex]Solving for x:
[tex]\begin{gathered} 1\cdot60=20\cdot x \\ \frac{60}{20}=x \\ 3\text{ in = x} \end{gathered}[/tex]The drop is 3 inches
