1. 4.7 Congruence Transformations
Then: You proved whether two triangles were congruent. Now: 1. Identify reflections, translations, and rotations. 2. Verify congruence after a congruence transformation.

2. 4.7 Congruence Transformations
Also called a rigid transformation or an isometry- where the original figure, or preimage, and the transformed image, or image figure, are congruent. Types of Transformations: Translations Reflections Rotations

3. Example 1: Identify transformations
Name the type of transformation demonstrated in each picture.
a b. c.
__________ __________ __________
about a point in a straight line in a vertical
line

4. Example 1
d. Identify the type of congruence transformation shown as a reflection, translation, or rotation.

5. Example 1
e. Identify the type of congruence transformation shown as a reflection, translation, or rotation.

6. Example 1
f. Identify the type of congruence transformation shown as a reflection, translation, or rotation.

7. Example 2
BRIDGES Identify the type of congruence transformation shown by the image of the bridge in the river as a reflection, translation, or rotation.

8. Example 2
GAME Identify the type of congruence transformation shown by the image of the chess piece as a reflection, translation, or rotation.

9. Example 3
Triangle PQR with vertices P(4, 2), Q(3, –3), and R(5, –2) is a transformation of ΔJKL with vertices J(–2, 0), K(–3, –5), and L(–1, –4). Graph the original figure and its image. Identify the transformation and verify that it is a congruence transformation.

10. Example 3- cont.
P(4, 2), Q(3, –3), and R(5, –2) J(–2, 0), K(–3, –5), and L(–1, –4).

11. 4.7 Assignment:
p #7-16 all, evens, 27, 29, 32, all, 46 Graph #18 & 20- use distance formula to verify congruence