Warm-Up Triangle ABC has the following vertices A(7, 2), B(1, 2), C(4, 5). 1.Give the coordinates of the image after is has been translated 3 units left and 2 units down. 2. That same triangle has been reflected across the y-axis. What are the coordinates of the image. Hint: You can draw a coordinate plane or use the rules that you have learned.

Transformation: Rotation Learn to recognize, describe, and show rotation on a coordinate grid. Agenda  Warm-Up  Notes/CW  Worksheet p. 5-6 Homework Complete pg Vocabulary 1.transformation 2.rotation 3.Rotational symmetry 4.Center of Rotation

Rotation The figure turns around a fixed point. The point can be on the figure or outside the figure. You can turn the figure 90, 180, 270, 360 degree rotation The point that a figure rotates around may be on the figure or away from the figure. Helpful Hint

Triangle ABC has vertices A(1, 0), B(3, 3), C(5, 0). Rotate ∆ABC 180° about the vertex A. Example 1: Graphing Rotations on a Coordinate Plane x y A B C 3 –3 The corresponding sides, AC and AC’ make a 180° angle. Notice that vertex C is 4 units to the right of vertex A, and vertex C’ is 4 units to the left of vertex A. C’ B’ A’

Triangle ABC has vertices A(0, –2), B(0, 3), C(0, –3). Rotate ∆ABC 180° about the vertex A. Example 2 The corresponding sides, AB and AB’ make a 180° angle. Notice that vertex B is 2 units to the right and 3 units above vertex A, and vertex B’ is 2 units to the left and 3 units below vertex A. x y B C 3 3 –3 B’ C’ A

A figure has rotational symmetry if, when it is rotated less than 360° around a central point, it coincides with itself. The central point is called the center of rotation.

Example 3: Identifying Rotational Symmetry Tell how many times each figure will show rotational symmetry within one full rotation. Draw lines from the center of the figure out through identical places in the figure. Count the number of lines drawn. The figure will show rotational symmetry 4 times within a 360° rotation.

Tell how many times each figure will show rotational symmetry with one full rotation. Example 4: Identifying Rotational Symmetry Draw lines from the center of the figure out through identical places in the figure. Count the number of lines drawn. The figure will show rotational symmetry 3 times within a 360° rotation.

Example 5 Tell how many times each figure will show rotational symmetry within one full rotation. Insert Lesson Title Here Draw lines from the center of the figure out through identical places in the figure. Count the number of lines drawn. The figure will show rotational symmetry 4 times within a 360° rotation.