How do you figure out scale factor?

To determine the scale factor between two similar figures, you can divide the length of a side of one figure by the corresponding side of the other figure. Ensure that both figures are in the same units before comparing. The scale factor can be expressed as a fraction, decimal, or ratio, and it indicates how much larger or smaller one figure is compared to the other. For example, if a side of the larger figure is 10 units and the corresponding side of the smaller figure is 5 units, the scale factor is 10/5, which simplifies to 2.