To find the scale factor of Martha's drawing, we start with the scale she used, which is \( 9 \) centimeters corresponding to \( 1 \) meter.
First, we need to express both measurements in the same unit. We will convert \( 1 \) meter to centimeters. Since \( 1 \) meter is equal to \( 100 \) centimeters, we can rewrite the scale as:
\[ 9 \text{ cm} = 100 \text{ cm} \]
Next, we can express the scale as a ratio:
\[ \frac{9 \text{ cm}}{100 \text{ cm}} \]
To find the scale factor, we simplify this fraction:
\[ \frac{9}{100} \]
Since \( 9 \) and \( 100 \) have no common factors other than \( 1 \), this fraction is already in its simplest form.
Thus, the drawing's scale factor is:
\[ \frac{9}{100} \]