Calculation:

If MNOP is a dilation of ABCD, then

The scale factor \(\displaystyle=\frac{{{M}{N}}}{{{A}{B}}}\)

The similarity ratio \(\displaystyle=\frac{{{A}{B}}}{{{M}{N}}}\)

Hence the scale factor and the similarity ratio are reciprocals.

If MNOP is a dilation of ABCD, then

The scale factor \(\displaystyle=\frac{{{M}{N}}}{{{A}{B}}}\)

The similarity ratio \(\displaystyle=\frac{{{A}{B}}}{{{M}{N}}}\)

Hence the scale factor and the similarity ratio are reciprocals.