To rearrange the formula for the area of a rectangle, \( A = l \times w \), to highlight the width \( w \) as the quantity of interest, you need to solve for \( w \).
Starting with the formula:
\[ A = l \times w \]
To isolate \( w \), divide both sides of the equation by \( l \):
\[ w = \frac{A}{l} \]
Now, Jason can use this rearranged formula to find the width of the garden. Given that the area \( A \) is 36 square meters and the length \( l \) is 9 meters, he can substitute these values into the equation:
\[ w = \frac{36}{9} \]
Calculating this gives:
\[ w = 4 \]
Therefore, the width of the garden is 4 meters.