Since the slope of the soil line is a quarter of an inch per foot and the drainage line is 50 feet long, then the difference in elevation is:
[tex]50\text{feet}\times\frac{1}{4}\frac{in}{feet}.[/tex]Simplifying the above expression we get:
[tex]\frac{50}{4}in=12.5in\text{.}[/tex]Recall that:
[tex]1\text{ in=}\frac{1}{12}feet.[/tex]Therefore:
[tex]12.5in\approx1.04\text{feet.}[/tex]Answer: 12.5 inches= 1.04 feet.
