Lesson 9.1: Help for Exercises 28-30 on page 532
For each of these exercises, you will write at least one proportion by applying the Geometric Mean Theorems given on page 529.
For Exercise 28, you can start by writing and solving a proportion that has c as the only variable. Once you know c, you can use simple algebra to find d. Once you know c and d, you can write and solve another proportion for e.
For Exercise 29, you can start by writing and solving a proportion that has x as the only variable. Then you can use the Pythagorean Theorem with each of the smaller triangles to find y and z.
For Exercise 30, you need to write only one proportion. To solve for x, remember that you can take the square root of each side of an equation. Check your answer.