The scale of the drawing is 3 millimeters = 1 meter. To find the scale factor, we need to express both measurements in the same units.
1 meter is equal to 1000 millimeters. Therefore, we can rewrite the scale as:
3 millimeters = 1000 millimeters.
Now we can write the scale factor as a ratio of the drawing measurement to the actual measurement:
3 millimeters : 1000 millimeters.
To simplify this ratio, we can divide both sides by 3:
1 : (1000 / 3) = 1 : 333.33 (approximately).
Thus, the simplified scale factor of the drawing is:
1 : 333.33 (or as a ratio, you may express it as 1 : 333 if rounding down is acceptable for your purposes).