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Chapter Seven

Proportions and Similarity

ratio comparison of two quantities using division
extended ratio Used to compare 3 or more quantities, a:b:c
proportion an equation that states two ratios are equal
cross products property In a proportion, the product of the extremes equals the products of the means
Equivalent Proportions a/b=c/d; b/a=d/c; a/c=b/d; c/a=d/b
similar polygons 2 polygons are similar if and only if their corresponding angles are congruent and corresponding side lengths are proportional.
scale factor The ratio of the lengths of the corresponding sides of 2 similar polygons. It depends upon the order of comparison.
Similarity and Congruence If two polygons are congruent, they are similar. All of the corresponding angles are congruent and the lengths of the corresponding sides have a ratio of 1:1
Identifying Similar Triangles When only 2 congruent angles of a triangle are given, remember you can use the THIRD ANGLE THEOREM to establish that the remaining corresponding angles are also congruent.
midsegment of a triangle segment with endpoints that are the midpoints of two sides of the triangle. Every triangle has 3 midsegments.
Created by: amgeometry