Suppose you have two similar figures , one larger than the other. The scale factor is the ratio of the length of a side of one figure to the length of the corresponding side of the other figure
generally to find scale factor you need to find how much larger or smaller the new image compared to the original. If it is larger it is represented as a ratio (example 1:2), if it is smaller it is represented as a fraction (example 1/2).
An example of finding scale factor would be a square with all the side lengths being 4cm (as the original) and the new square having all side lengths of 8 cm.
The scale factor would be 1 : 2 because the new image is 2 times the size of the original.
