$y$ varies directly with $x$. $y$ is 72 when $x$ is 9 . What is $y$ when $x$ is 17 ?

Step 1 ：This problem involves direct variation, which means as one quantity increases, the other also increases, and vice versa. The formula for direct variation is \(y=kx\), where \(k\) is the constant of variation.

Step 2 ：We are given that \(y\) is 72 when \(x\) is 9. We can use these values to find the constant of variation \(k\).

Step 3 ：Substituting the given values into the formula, we get \(72=k*9\). Solving for \(k\), we find that \(k=8.0\).

Step 4 ：Now that we have the value of \(k\), we can find the value of \(y\) when \(x\) is 17.

Step 5 ：Substituting \(x=17\) and \(k=8.0\) into the formula, we get \(y=8.0*17\), which simplifies to \(y=136.0\).

Step 6 ：Final Answer: The value of \(y\) when \(x\) is 17 is \(\boxed{136}\).