To find the scale factor of Franco's drawing, we start with the given scale: 7 millimeters = 1 meter.
First, we need to express both quantities in the same unit for clarity. Since the scale is given in millimeters, we convert 1 meter to millimeters.
1 meter = 1000 millimeters.
Now we can set up a ratio to express the scale factor. The scale factor compares the drawing size (in millimeters) to the actual size (in millimeters).
The scale can be written as:
\[ \text{Scale factor} = \frac{\text{Drawing size (mm)}}{\text{Actual size (mm)}} = \frac{7 \text{ mm}}{1000 \text{ mm}} \]
Now, we simplify this fraction:
\[ \text{Scale factor} = \frac{7}{1000} \]
Thus, the scale factor of the drawing is:
\[ \frac{7}{1000} \]