Verify that the figures are similar. Similar figures, or shapes, are ones in which the angles are congruent, and the side lengths are in proportion.
Find a corresponding side length on each figure. You may need to rotate or flip the figure so that the two shapes align and you can identify the ...
Set up a ratio. For each pair of similar figures, there are two scale factors: one you use when scaling up, and one you use when scaling down. If ...
Simplify the ratio. The simplified ratio, or fraction, will give you your scale factor. If you are scaling down, your scale factor will be a proper answer