Transcript Rotations

ROTATIONS
Unit 10 Notes
A rotation is a transformation in which a
figure is turned about a fixed point. The
fixed point is called the center of rotation.
Rays drawn from the center of rotation to a
point and its image form an angle called the
angle of rotation.
The angle of rotation
can be measured
clockwise (CW) or
counterclockwise
(CCW).
Can you
describe the
rotation?
Is there only one
way to describe
the rotation?
A figure in the plane has rotational
symmetry if the figure can be mapped onto
itself by a rotation of 180° or less.
A rotation is
an isometry!
ROTATIONS ABOUT THE ORIGIN
90° CCW about the origin 270˚ CW
180° CW or CCW
about the origin
270° CCW or 90˚CW
about the origin
PRACTICE #1
Rotate ∆ABC with vertices A(2,-1) ,
B(4,1), and C(3,3) by 90° about the origin.
PRACTICE #2
Rotate ∆ABC with vertices A(2,-1) , B(4,1),
and C(3,3) by 180° about the origin.
PRACTICE #3
1.90˚ CW rotation of
𝐴𝐵 about X
2.180˚ CCW rotation
of 𝐺𝐻 about X
3. 45˚ CCW rotation
of ΔAXB
CLASSWORK AND HOMEWORK
Handout 7.3A and 7.3B