Sewanhaka High School
Math 8
Per:________________
Name:________________________________
Mrs. Lidowsky, Principal
Mr. Long, Teacher
Date:_____________________
H.W. #51: Ditto
DO-NOW #51:
1) Locate ∆ABC by plotting and connecting the following points:
A(1, 1) B(1, 4) C(5, 1)
Find the image of ΔABC under the dilation of D2. Give the
coordinates of A’, B’, and C’.
A(1, 1) → A’(
,
) → A’( , )
B(1, 4) → B’(
,
) → B’( , )
C(5, 1) → C’(
,
) → C’( , )
2) Solve for x:
4
x
=
12 9
3) Multiply: 2b3(3b4)
Topic: Transformations
Main Idea: Rotations
Aim:
RECALL
Locate ΔABC by plotting and connecting the
following points: A(4, 2) B(2, 2) C(2, 6)
Turn your paper 90 degrees counterclockwise.
Note the coordinates of ΔABC now. Write them
down, then locate ΔA’B’C’.
Rotate ΔABC 90° counterclockwise about the
origin. Label the image ΔA’B’C’. Give the
NOTES
coordinates of A’, B’, and C’.
Answer:
A(4, 2) → A’(
B(2, 2) → B’(
C(2, 6) → C’(
,
,
,
) → A’(
) → B’(
) → C’(
,
,
)
)
,
)
Find the area of each triangle. How do they
compare?
Find the image of each point under a rotation of
90° counterclockwise about the origin:
A(1, 3) → A’(
B(2, 4) → B’(
C(-1, 2) → C’(
D(-3, -2) → D’(
E(0, 2) → E’(
F(x, y) → F’(
,
,
,
,
,
,
) → A’(
,
)
) → B’(
,
)
) → C’(
,
)
) → D’(
,
)
) → E’(
,
)
) → F’(
,
)
Locate ΔABC by plotting and connecting the
following points: A(4, 2) B(2, 2) C(2, 4)
Question: Rotate ΔABC 180° about the origin.
Label the image ΔA’’B’’C’’. Give the coordinates
of A’’, B’’, and C’’.
Answer:
A(4, 2) → A’’( ,
)
B(2, 2) → B’’( ,
)
C(2, 4) → C’’( ,
)
Can you come up with a rule for rotating 180°
counterclockwise about the Origin?
Where have you seen this rule before?
Drill: Locate ∆GHI by plotting and connecting
the following points: G(6, 0) H(0, 3) I(9, 6).
Rotate ∆GHI 90° clockwise about the origin.
Label the image ∆G’H’I’. Give the coordinates of
G’, H’, and I’.
Answer:
G(6, 0) → G’(
,
) → G’(
, )
H(0, 3) → H’(
,
) → H’( ,
)
I(9, 6) → I’(
,
) → I’( ,
)
Questions: Which figures have point
symmetry and why?
Summary: