TransformationsRotations, Dilations

Vocabulary Today

Objectives today…

Turning a figure about a point

(center of rotation) for a certain number

of degrees (∠ of rotation)

counter-clockwise

1 3 -13 -5-1 -5

-1 -3-5 -3-5 1

1

y -x

-x -y

-y x

Technology Break

5 min

clockwise

1 1 35 35 -1

1 3 -13 -5-1 -5

y -x

-x -y-y x

Using a scale factor to make a

figure larger or smaller (needs to

maintain the same shape!)great

er0 1

-4 -4-2 44 1

ENLARGEMENT

2x 2y

(4/2, 3/2)

(2, 1.5)(7/2, -1/2)

(3.5, -.5)(2/2, -2/2)

(1, -1)

A’

B’C’

REDUCTION

(2, 6)(3.5, -2)(1, -4)

A’

B’C’ NEITHER. NOT A

DILATION

Technology Break

5 min

Look at how a point changes3*s = 2 and 6*s = 4s = 2/3 and s = 4/6

M’ (8, -2)A’ (18, -4)T’ (6, 12)H’ (0, 0)

s = 2

(x, y) (2x, 2y)

2/3

Vocabulary Revisited

HomeworkRotations and Dilations Practice

Shark Story

Shark Story Graphs

1st Graph: › Original Shark› Translated Shark› Reflected Shark

2nd Graph: › Shark Lenny› His hat and

rotated hat 3rd Graph:

› Original Shark› His hat and

rotated hat

Label your points› Original: A, B, C,

…› Translated: A’, B’,

C’,…› Reflected: A’’, B’’,

C’’, …› Shark Lenny you

may say A, B, C…(since on separate graph)

› Rotated Hats: Z’, Y’, X’…