Scale Factor

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.


Two similar triangles UVW and XYZ with UV = 3, VW = 4, WU = 5, and XY = 12

Here, XY/UV = 12/3 = 4. So, the scale factor is 4.

Note that when a two-dimensional figure is enlarged (dilated) by a scale factor of k, the area of the figure is changed by a factor of k2, and the volume is changed by a factor of k3.