2 DefinitionsDilation - a transformation in which every point P has an image P' placed on OP so thatand OP' = k * OPCenter of Dilation – the point from which an original figure is dilated.Scale Factor - the ratio of the image length to the corresponding original length.
3 Scale FactorIf the scaled factor is greater than 1, then it is an enlargement (k>1).If the scaled factor is equal to 1, then it is a congruent figure (k=1)If the scale factor is less than 1, then it is a reduction (k<1).
4 This dilation is an enlargement . Corresponding distances Image Distance42= = 2= kScale FactorOriginal Distance2 > 1This dilation is an enlargement .Corresponding distances
5 This dilation is an reduction. Corresponding distances Image Distance23== kScale FactorOriginal Distance2/3 < 1This dilation is an reduction.Corresponding distances
6 Example:Rectangle W’X’Y’Z’ is the image of rectangle WXYZ after a dilation.Find the scale factor of the dilation.Tell whether the image is a reduction or an enlargement.