1. Do Now Find the missing of the following angles: Hint: Find the angles in the order I wrote them. Make sure you use what you know about sum of interior angles, supplementary angles and vertical angles.

2. Objective: [] identify corresponding parts in congruent triangles [] determine if 2 triangles are congruent Agenda: [] Congruent Triangle Activity -- How do we know triangles are congruent? [] Discussion [] Start Practice [] hand back quizzes, gradekeepers, etc. Homework: [] 4-3 study guide handout (#1-6)

3. Congruent Triangle Activity 1) What does congruent mean? 2) How do we know if 2 triangles are congruent For the pile of triangles I give you, group them in sets of congruent triangles. Next for each set, have a group member measure all the sides and angles of those 2 triangles. Record your measurements on the handout provided.

4. Discussion What did you observe about the side lengths and angle measurements between your two triangles? Based on what you’ve learned, how can you test that two triangles are congruent?

5. ∆ABC is congruent to ∆XYZ AB C XY Z

6. AB C XY Z Corresponding parts of congruent triangles are congruent!!! Corresponding parts are angles and sides that “match.”

7. p. 217

8. ∆FGH is congruent to ∆JKL G F H J KL Name all corresponding parts.

9. ∆EFG is congruent to ∆HFG H G F E Name all corresponding parts.

10. Are these two triangle congruent? Explain why or why not. Then name the 2 congruent triangles.