scale factor

This is the term used for a number that determines the size of an enlargement.

For example, if the scale factor is 3, the enlargement will be three times the size of the original shape.

If the scale factor is between 0 and 1, the enlargement will be smaller than the original shape.

If the scale factor is negative, the enlargement will appear on the other side of the centre of enlargement. The new shape will be upside down.