what is the scale factor of the dilation?

Answer: The scale factor of the dilation was 2.Step-by-step explanation: It is important to remember that the original figure (before the transformation) is called "Pre-Image" and the figure obtained after the transformations is called "Image". In this case, the Pre-Image would be Dave's pupils before dilation and the Image would be Dave's pupils after the dilation. Then, according to the information given in the exercise, you know  that Dave's pupils before dilation had the following diameter: [tex]d_1=4.1\ mm[/tex] And, after dilation, the diameter of his pupils was: [tex]d_2=8.2\ mm[/tex] Therefore, the scale factor "k" of the dilation is given by: [tex]k=\frac{d_2}{d_1}[/tex] Finally, substituting values, you get that the scale factor was: [tex]k=\frac{8.2\ mm}{4.1\ mm}\\\\k=2[/tex]