7-1 Proportions Ratio – a comparison of two numbers using division Proportion – an equation of the form a/b = c/d that states that two ratios are equivalent Cross Product – 224(150) = 100(336) extreme means b, d can not equal zero
Example Polygon RSTUV is similar to polygon ABCDE The ratio of lengths of corresponding sides of similar polygons is called the Scale Factor. The scale factor of RSTUV to ABCDE is 18:4. The scale factor of ABCDE to RSTUV is 4:18. How else could these scale factors be stated? What are the values for x and y?
Example Triangle ABC has vertices A(0, 0), B(4, 0), and C(2, 4). If the coordinates of each vertex are multiplied by 2, will the new figure be similar to the original?