1. **State the problem:** Keisha used a photo measuring 4 inches by 6 inches and made a copy measuring 8 inches by 12 inches. We need to find the scale factor of the dilation. 2. **Formula for scale factor:** The scale factor $k$ in a dilation is the ratio of any length in the image to the corresponding length in the original figure. 3. **Calculate scale factor using width:** Original width = 4 inches, new width = 8 inches. $$k = \frac{\text{new width}}{\text{original width}} = \frac{8}{4}$$ 4. **Simplify the fraction:** $$k = \frac{\cancel{8}}{\cancel{4}} = 2$$ 5. **Calculate scale factor using height:** Original height = 6 inches, new height = 12 inches. $$k = \frac{12}{6}$$ 6. **Simplify the fraction:** $$k = \frac{\cancel{12}}{\cancel{6}} = 2$$ 7. **Conclusion:** Both width and height scale factors are equal to 2, so the scale factor of the dilation is $2$. This means the copy is twice as large as the original in both dimensions.