The scale factor is usually calculated with:
[tex]=\frac{\text{image length}}{object\text{ length}}[/tex]
From the question, the dimension with the dotted line is the image, while the dimension with the bold line is the object.
So the scale factor therefore is:
[tex]\begin{gathered} =\frac{1in}{2in} \\ =\frac{1}{2} \end{gathered}[/tex]
