1 Warm Up

2 Section 4.3 Relate Transformations and CongruenceObjective: SWBAT use transformations to prove congruence.

3 Vocabulary: Transformation: a move or change in a figure to produce a new figure Rigid Motion/Isometry: a transformation that preserves length, angle measure and area. Translation: a transformation that moves every point of a figure the same distance in the same direction Rotation: a transformation in which a figure is turned about a fixed point called the center of rotation Reflection: a transformation that uses a line of reflection to create a mirror image of the original figure

4 Describe rigid motions to show congruenceDescribe the transformation(s) you can use to move the blue figure onto the red figure. 1. 2. SOLUTION 1. rotation about P 2. translation and then reflection

5 Describe rigid motions to show congruenceDescribe the transformation(s) you can use to move the blue figure onto the red figure. 3. 4. ANSWER ANSWER translation and then rotation translation and then reflection

6 Describe rigid motions to show congruenceDaily Describe rigid motions to show congruence 5. Identify the transformation(s) you can use to move figure A onto figure B. ANSWER translation, then reflection

7 Describe rigid motions to show congruenceDaily Homework Quiz Describe rigid motions to show congruence 6. Tell whether a rigid motion can move figure A onto figure B. Explain. ANSWER No; a reflection maps one side to a congruent side, but the other sides are not congruent.

8 Transformation Rules Find the image of the points after the transformation whose rule is given. 1. (–4, 3), (1, 4), (2, –5), (x, y) → (x – 2, y + 1) ANSWER (–6, 4), (–1, 5), (0, –4) 2. (–2, 1), (3, 5), (–1, –4), (x, y) → (–y, x) ANSWER (–1, – 2), (–5, 3), (4, –1) 3. (2, –4), (–3, 4), (4, –2), (x, y) → (–x, y) ANSWER (–2, –4), (3, 4), (–4, –2)

9 Homework Page 227 # 4-16 (evens)