we know that
[tex]1\ yard=3\ feet[/tex]
Let
y-------> the number of feet that are in x yards
by proportion
Find the value of y
[tex]\frac{3}{1} \frac{feet}{yard}=\frac{y}{x} \frac{feet}{yards} \\ \\y=3x\ feet[/tex]
therefore
the answer is the option C
[tex]3x[/tex]
