A scale factor is a number that is used to change the size of a figure without changing its shape. It is the ratio between corresponding measurements of an object and a representation of that object. The scale factor can be expressed as a fraction or a colon. If the scale factor is a whole number, the copy will be larger, and if it is a fraction, the copy will be smaller. The scale factor can be used to compare two similar geometric shapes and also in other fields like cooking, where the ingredients can be reduced or increased according to the given situation. The formula for the scale factor is given by: Dimensions of Original Shape x Scale Factor = Dimension of new shape. The scale factor can be calculated if the dimensions of the original figure and the dimensions of the dilated (increased or decreased) figure are known. The scale factor is used to scale shapes in different dimensions.