ClassZone: Geometry - Problem Solving Help

Problem Solving Help

3.5 Using Properties of Parallel Lines

Lesson 3.5: Help for Exercises 25-29 on page 161

For Exercises 25 and 26, turn back to page 159 and find the first construction shown, Copying an Angle. Notice that is given and is constructed so that and are congruent. Or, we can say that is "copied." In Exercise 25, you will start by drawing an that is acute (measures less than 90°). In Exercise 26, you will start by drawing an that is obtuse (measures between 90° and 180°). For each step of the construction, read the words and look carefully at the diagram, then complete the step with your . If you become confused by all the letters that are used to label the points, ignore them and instead look at the diagrams to see exactly what is done in each step. It is not necessary to label your construction the same as the diagrams in book show, unless it helps you. Your goal need only be to construct a congruent angle.

For Exercises 27 and 28, turn back to page 159 and find the second construction shown, Parallel Lines. For practice and to see how it works, complete this construction by following the four steps given. Then use the construction to do the exercises.

For Exercise 29, look back at your work in Exercise 28. What type of congruent angles did you construct? What postulate or theorem is based on this type of congruent angles?