Rules of Rotation
Objective: Use the rotation rules to rotate images on the coordinate plane.
1
Graph A(5, 2), then graph B,
the image of A under a 90°
counterclockwise rotation
about the origin.
A (5, 2)
Rule for 90° counterclockwise rotation:
2
Now graph C,
the image of A under a 180°
counterclockwise rotation
B (- 2, 5)
A (5, 2)
about the origin.
Rule for 180° counterclockwise rotation:
3
Now graph D,
the image of A under a 270°
B (- 2, 5)
A (5, 2)
counterclockwise rotation
about the origin.
C (- 5, - 2)
Rule for 270° counterclockwise rotation:
4
What type of quadrilateral is
ABCD? Why?
B (- 2, 5)
A (5, 2)
C (- 5, - 2)
D (2, - 5)
5
Rotations (counterclockwise)
Rotation of 90° (x, y) → ( ‐ y, x )
Rotation of 180° (x, y) → ( ‐ x, ‐ y )
Rotation of 270° (x, y) → ( y, ‐ x )
______________________________
______________________________
______________________________
6
Rotate triangle ABC 90° counterclockwise.
Find the coordinates of the image of each of the vertices.
7
HW # 37 Rotation Rules Worksheet
8