90° ROTATIONS
Rotate (3, 2) 90° counterclockwise.
(−2, 3)
Rotate (2, 3) 180° about the origin
(−2, −3)
Rotate (3, 4) 270° counterclockwise.
(4, −3)
Rotate (2, 3) 90° clockwise.
(3, −2)
Does a rotation change the shape or size?
No
Rotate (−4, 1) 90° counterclockwise.
(−1, −4)
Rotate (−5, 4) 180° about the origin
(5, −4)
Rotate (−2, 5) 270° counterclockwise.
(5, 2)
Rotate (−4, 2) 90° clockwise.
(2, 4)
What point do rotations in this lesson happen around?
The origin (0,0)
Rotate (5, −2) 90° counterclockwise.
(2, 5)
Rotate (6, −1) 180° about the origin
(−6, 1)
Rotate (6, −3) 270° counterclockwise
(−3, −6)
What is the rule for 90° clockwise rotation?
(x, y) → (y, −x)
A point returns to its original position after what rotation?
360°
What is the rule for 90° counterclockwise rotation?
(x, y) → (−y, x)
What is the rule for 180° rotation about the origin?
(x, y) → (−x, −y)
What is the rule for 270° counterclockwise rotation?
(x, y) → (y, −x)
Is 270° counterclockwise the same as 90° clockwise?
Yes
Which rotation gives the same result as reflecting over both axes?
180° rotation
Rotate triangle A(1,2), B(3,2), C(2,4) 90° counterclockwise
A′(−2,1), B′(−2,3), C′(−4,2)
Rotate triangle A(2,1), B(4,3), C(3,5) 180° about the origin
A′(−2,−1), B′(−4,−3), C′(−3,−5)
Rotate triangle A(1,3), B(2,5), C(4,2) 270° counterclockwise rotation
A′(3,−1), B′(5,−2), C′(2,−4)
Rotate (5, −1) 90° clockwise
(−1, −5)
True or False: A student says 90° CCW rule is (x, y) → (y, x). If false, correct it
False (−y, x)