The problem states that $y$ is directly proportional to $x$, and we are given that $y = 9$ when $x = 63$.

In mathematical terms, direct proportionality is written as:

$y = kx$

where $k$ is the constant of proportionality. To find $k$, we use the given values $y = 9$ and $x = 63$:

$9 = k \times 63$

Solving for $k$:

$k = \frac{9}{63} = \frac{1}{7}$

Thus, the formula describing the situation is:

$y = \frac{1}{7}x$

Let me know if you'd like more details or further questions!

Here are 5 related questions:

1. What happens to $y$ when $x$ doubles in this formula?
2. How would the formula change if $y$ was inversely proportional to $x$?
3. If $x = 49$, what is the value of $y$?
4. How would you express this relationship graphically?
5. What is the significance of the constant $k$ in proportional relationships?

Tip: For direct proportionality, as one variable increases, the other increases at a constant rate.