Sewanhaka High School
Math 8
Per:________________
Name:________________________________
Mrs. Lidowsky, Principal
Mr. Long, Teacher
Date:_____________________
H.W. #50: Ditto
DO-NOW #50:
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 translation of T-3, 2. Give the
coordinates of A’, B’, and C’.
A(1, 1) → A’(
,
) → A’(
, )
B(1, 4) → B’(
,
) → B’( ,
)
C(5, 1) → C’(
,
) → C’(
,
)
2) Divide:
2
5
÷1 =
9
9
3) Find 20% of 40.
Topic: Transformations
Main Idea: Dilations
Aim:
RECALL
Locate ΔABC by plotting and connecting the
following points: A(4, 2) B(2, 2) C(2, 4)
NOTES
Find the image of ΔABC after a dilation with a
scale factor of 2 (D2) in 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’(
,
,
,
) → A’(
) → B’(
) → C’(
,
,
)
)
,
)
What happened to the coordinates of ΔABC under
the previous dilation?
Find the area of each triangle. How do they
compare?
Find the image of each point under the given
dilation:
D2:
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’(
,
)
Find the image of each point under the given
dilation:
D3:
Question: What is the rule for a dilation of a in the
Origin?
Locate ΔABC by plotting and connecting the
following points: A(4, 2) B(2, 2) C(2, 4)
Find the image of ΔABC after a dilation with a scale
factor of ½ (D½) in the origin. Label the image
ΔA’’B’’C’’. Give the coordinates of A’’, B’’, and C’’.
Answer:
A(4, 2) → A’’(
,
) → A’’( ,
)
B(2, 2) → B’’(
,
) → B’’(
, )
C(2, 4) → C’’(
,
) → C’’( ,
)
What happened to the coordinates of ΔABC under
the previous dilation?
Find the area of each triangle. How do they
compare?
Locate ∆GHI by plotting and connecting the
following points: G(2, 0) H(0, 1) I(3, 2).
Find the image of ∆GHI under D2:
a) D2
Give the coordinates of G’, H’, and I’.
Answer:
G(2, 0) → G’(
,
) → G’(
,
H(0, 1) → H’(
,
) → H’(
,
I(3, 2) → I’(
,
) → I’(
,
)
)
)
b) D3
Give the coordinates of G’’, H’’, and I’’.
Answer:
G(2, 0) → G’’(
H(0, 1) → H’’(
I(3, 2) → I’’(
Summary:
,
,
,
) → G’’(
) → H’’(
) → I’’(
,
,
,
)
)
)
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’(
,
)