Scale factor also called similarity ratio is defined by the ratio between the lengths of the polygon sides:
Then, scale factor would be:
[tex]SF=\frac{\text{length from figure B}}{\text{length from figure A}}[/tex][tex]\begin{gathered} SF=\frac{5}{2} \\ SF=2.5 \end{gathered}[/tex]
Scale factor is 2.5 units.
