To find an ordered pair \((x, y)\) that satisfies the equation \(y = x\) with an \(x\)-coordinate of 3, we can simply use the equation itself.
Since the equation \(y = x\) states that \(y\) is equal to \(x\), we can substitute \(x = 3\):
\[ y = 3 \]
Thus, the ordered pair \((x, y)\) is:
\[ (3, 3) \]
So the additional ordered pair that satisfies the equation \(y = x\) with an \(x\)-coordinate of 3 is \((3, 3)\).