To find the scale factor k, we need to calculate the ratio between the image and the preimage.
scale factor=image length/preimage length
The image is what we have after the dilation. In this case, the image is a dilated photo with a dimension of 5inches by 7inches. The preimage, which in this case is the original photo, has a dimension of 2.5inches by 3.5inches. To calculate k, we can substitute either pair of the corresponding sides. Let's choose the shorter ones.
