Answer:
The Direct Variation says that:

Then; the equation becomes:
where k is the constant of variation.
Let y represents the number of feet and f(y) represents the number of yards.
then;
by definition of direct relationship we have;

Substitute any values from the given tables to solve for k;
Let y = 3 and f(y) = 1
then;

Divide both sides by 3 we get;

then, the model of the equation becomes:

In Words :
times the number y.
Variable : Let y represents the number of feet.
Model :

An algebraic expression to represents the number of feet in any number of yards,
