1. Class Greeting

2. Objective: The students will be able to identify congruent triangles, find corresponding parts of congruent triangles and transform congruent triangles.

3. Chapter 4 – Lesson 2
Congruent Triangles

4. Vocabulary
Corresponding
Matching according to some agreed rule

5. Definition Congruent Triangles
We say triangles ABC and DEF are congruent if and only if all their corresponding parts are congruent (CPCTC)
We write ABC  DEF
A corresponds to D; B to E; C to F

6. ARCHITECTURE A tower roof is composed of congruent triangles all converging toward a point at the top. Name the corresponding congruent angles and sides of HIJ and LIK.
HIJ
LIK
Answer: Since corresponding parts of congruent triangles are congruent,
Example 3-1a

7. Name the congruent triangles.
ARCHITECTURE A tower roof is composed of congruent triangles all converging toward a point at the top.
Name the congruent triangles.
Answer: HIJ LIK
Example 3-1b

8. The support beams on the fence form congruent triangles.
b. Name the congruent triangles.
a. Name the corresponding congruent angles and sides of ABC and DEF.
Answer:
Answer: ABC DEF
Example 3-1c

9. Vocabulary Congruence Transformation
A function that changes a triangle into a new triangle congruent to the original
We’ll look at 3 congruence transformations:
Slide
Turn
Flip

10. Congruence Transformation Slide
Slides are often called translations

11. Congruence Transformation Turn
Turns are often called rotations

12. Congruence Transformation Flip
Flips are often called reflections

13. Answer: RST is a turn of RST.
COORDINATE GEOMETRY The vertices of RST are R(─3, 0), S(0, 5), and T(1, 1). The vertices of RST  are R(3, 0), S(0, ─5), and T(─1, ─1). Name the congruence transformation for RST and RST.
Answer: RST is a turn of RST.
Example 3-2d

14. b. Name the congruence transformation for ABC and ABC.
Answer: turn
Example 3-2g

15. Theorem 4.3 Third Angle Theorem
If two angles of a triangle are congruent to two angles of a second triangle then the third angles of the two triangles are also congruent

17. Kahoot!

18. Lesson Summary:
Objective: The students will be able to identify congruent triangles, find corresponding parts of congruent triangles and transform congruent triangles.

19. Preview of the Next Lesson:
Objective: The students will be able to Prove Congruence – SSS and SAS.

20. Stand Up Please