Question

Carmen measured a house and made a scale drawing. The scale of the drawing was 9 millimeters = 1 meter. What is the drawing's scale factor? Write it as a fraction.

Answer 1

When you write a scale factor, the units have to be the same.  In this case, 9mm on the drawing represents 1 meter on the house.  Change 1 meter to millimeters (1m = 1000mm).

9 mm on the drawing represents 1000 mm on the house.

The scale factor is 9 to 1000, or, as a fraction,  9/1000.