Let's begin by identifying key information given to us:
The rectangle on the right has a dimension of 8 by 4
The rectangle on the left has a dimension of 6 by 3
The scale factor is given by the ratio of the image to the pre-image:
![\begin{gathered} sf==\frac{\text{Smaller Length}}{Larg\text{er Length}}=(6)/(8)=(3)/(4) \\ sf=(3)/(4)=0.75 \\ sf=0.75 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/avep50nhhhwisgsy7l8bww8d0fm7me88zs.png)
Therefore, the scale factor is 0.75