You have 700 feet of fencing to enclose a rectangular playground and subdivide it into two smaller playgrounds by placing the fencing parallel to one of the sides, as shown in the figure. Express the area of the playground, $A$, as a function of one of its dimensions, $x$.

Step 1 ：Let's denote the length of the rectangle as \(x\) and the width as \(y\). The total length of the fencing is 700 feet, which gives us the equation \(3x + 2y = 700\).

Step 2 ：We can express \(y\) as a function of \(x\) from this equation, which gives us \(y = 350 - \frac{3}{2}x\).

Step 3 ：The area of the rectangle is \(A = x*y\). We can substitute \(y\) from the first equation into the second to express \(A\) as a function of \(x\).

Step 4 ：Substituting \(y\) into the area equation gives us \(A = x*(350 - \frac{3}{2}x)\).

Step 5 ：Final Answer: The area of the playground, \(A\), as a function of one of its dimensions, \(x\), is \(\boxed{A = x*(350 - \frac{3}{2}x)}\).