1. Ratio and Proportion cdcd abab = proportion: two ratios that are equal to each other. cross products of proportions are equal (b)(c) = (a)(d) Review: 2323 3w3w = Solve for each variable. 10 y 2y 5 = 1.) 2.) You must check for solutions that would not work. Any value of "x" that makes the denominator zero is undefined. This is called an extraneous solution.

2. -3 d d - 3 2d = x + 3 4 x5x5 = 3.) 4.)

3. x + 3 x + 5 x - 3 -5 = 2x - 3 4x x - 1 x = 5.) 6.)

4. Demonstrate Understanding: 1.) 2.) 3.) 4.)