1. Find the coordinates of A(3, 2) reflected in the line y = 1.
Session Warm-up
Find the coordinates of A(3, 2) reflected in the line y = 1.
Find the coordinates of B (-2, 4) reflected in the y-axis.
Find the measure of a counterclockwise rotation that would equal each rotation. Think.
180 clockwise rotation
90 clockwise rotation

2. Center of Rotation Angle of Rotation Rotational Symmetry
7.3 Rotations
Center of Rotation
Angle of Rotation
Rotational Symmetry

3. ROTATIONAL SYMMETRY – Any figure that can be turned or rotated less than 360° about a fixed point so that the figure looks exactly as it does in its original position.

4. Rotational Symmetry in the parking lot

6. Which figures have rotational symmetry
Which figures have rotational symmetry? For those that do, describe the rotation that map the figure onto itself.
Regular pentagon
Rhombus
Isosceles triangle NO NO

7. Rotation is simply turning about a fixed point.
Rotate
90 counterclockwise
about the origin
Rotate
180
about the origin
Rotate 90clockwise about the origin

8. Rotate 90 degrees clockwise about the origin.
Change the sign of x
&
switch the order of x and y.
Same as 270 counterclockwise

9. Example: Rotate 90 degrees clockwise about the origin.

10. Rotate 90° clockwise about the origin

11. Rotate 90 degrees counterclockwise about the origin.
Change the sign of y
&
Switch the order of x and y
Same as 270 clockwise

12. Example: Rotate 90 degrees counterclockwise
about the origin.

13. Rotate 90° counterclockwise about the origin

14. change the sign of both x & y.
Rotate 180 degrees
about the origin.
Keep the order
&
change the sign of both x & y.

15. Example: Rotate 180 degrees about the origin.

16. Rotate 180° about the origin

17. Find the angle of rotation that maps ABC onto A’’B’’C’’.
C’ B’ A
B C
B’’ A’’
C’’ k m

18. Classwork pg. 416 #6-14, 17-19, 30-38, 43