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8.1 Dilations and Scale Factors Objectives: Construct a dilation of a segment and a point by using a scale factor Construct a dilation of a closed plane figure Vocab: Dilation~ An example of a tranformation that is not rigid Scale Factor~ The number //n// Contraction~ If the size of a figure is reduced by a dilation Expansion~ If the size of a figure is enlarged by a dilation

8.2 Similar Polygons Objectives: Define //similar polygons// Use Properties of Proportion and scale factors to solve problems involving similar polygons Two figures are similar if and only if one is congruent to the image of the other by dilation (The symbol ~ means similar. Ex: ABC~A'B'C') Two polygons are similar if and only if there is a way of setting up a correpondence between their sides and angles such that the following conditions are met: -Each pair of corresponding angles is congruent -Each pair of corresponding sides is proportional Let //a//, //b//, //c//, and //d// be any real numbers If a/b = c/d and b and d do not = 0, then ad=bc Reciprocal Property if a/b = c/d and a, b, c, and d do not = 0, then b/a = d/c
 * Definition: Similar Figures**
 * Polygon Similarity Postulatere**
 * __Properties of Proportions__**
 * Cross-Multiplication Property**