Notes in Rotations
Notes in Rotations
Notes in Rotations
A
rotation
is
a
transformation
that
turns
a
figure
about
a
fixed
point
called
the
center
of
rotation.
An
object
and
its
rotation
are
the
same
shape
and
size,
but
the
figures
may
be
turned
in
different
directions.
Rotations
can
occur
in
either
a
clockwise
or
counterclockwise
direction.
The
figure
does
not
change
size.
Notice
that
a
rotation
of
180° about
the
origin
is
the
same
as
a
point
reflection.
A
rotation
of
360°
would
match
the
image
with
its
preimage.
A
positive
angle
of
rotation
turns
the
figure
counterclockwise,
and
a
negative
angle
of
rotation
turns
the
figure
in
a
clockwise
direction.
Counterclockwise
Clockwise
Rule
𝑅!"
𝑅!!"#
(𝑥, 𝑦) → (−𝑦, 𝑥)
𝑅!"#
𝑅!!"#
(𝑥, 𝑦) → (−𝑥, −𝑦)
𝑅!"#
𝑅!!"
(𝑥, 𝑦) → (𝑦, −𝑥)
Notice
that
degree
movement
on
a
unit
circle
goes
in
a
counterclockwise
direction.
You
will
want
to
remember
the
layout
of
the
unit
circle
when
you
are
graphing
figures
and
their
rotations.
Examples
1.
What
is
the
image
of
the
point
(6, −3)
under
the
rotation
𝑅!"
about
the
origin?
2.
What
is
the
image
of
the
point
(−5, 10)
under
the
rotation
𝑅!"#
about
the
origin?
3.
What
is
the
image
of
the
point
(2,4)
under
the
rotation
𝑅!!"
about
the
origin?
4.
A.
Graph
and
label
∆𝐽𝐾𝐿
with
vertices
J(2,
2),
K(4,
–5),
and
L(–1,
6)
B.
Graph,
label
and
state
the
coordinates
of
∆𝐽′𝐾′𝐿′,
the
image
of
∆𝐽𝐾𝐿
after
a
rotation
of
180°
about
the
origin.
5.
A
rectangle
is
plotted
on
the
coordinate
plane
below.
Draw
the
image
of
this
rectangle
after
the
rotation
𝑅!!" .
6.
A
triangle
is
plotted
on
the
coordinate
plane
below.
Draw
the
image
of
this
triangle
after
the
rotation
𝑅!" .
7.
A
clockwise
rotation
of
90°
is
the
same
as
a
counterclockwise
rotation
of
____________.
8.
A
clockwise
rotation
of
180°
is
the
same
as
a
counterclockwise
rotation
of
____________.
9.
A
clockwise
rotation
of
270°
is
the
same
as
a
counterclockwise
rotation
of
____________.
10.
A
rotation
of
360°
is
the
same
as
a
rotation
of
____________.
11.
The
drawing
below
shows
a
rotation
of
____________
or
______________.
NYS COMMON CORE MATHEMATICS CURRICULUM Lesson 13 M1
GEOMETRY
Exit Ticket
Find the center of rotation and the angle of rotation for the transformation below.