Pearson Geometry Common Core, 2011
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Pearson Geometry Common Core, 2011 View details
8. Geometric Probability
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Exercise 54 Page 674

The transformation T_(<-3,4>)∘ r_((90^(∘),O))(△ ABC) can be written as T_(<-3,4>)(r_((90^(∘),O))(△ ABC)). This means that △ABC will be rotated 90^(∘) about the origin O and then the image will be translated 3 units to the left and 4 units up.

A''(-5,6), B''(-4,3), C''(-2,5)

Practice makes perfect

The transformation T_(<-3,4>)∘ r_((90^(∘),O))(△ ABC) can be written as T_(<-3,4>)(r_((90^(∘),O))(△ ABC)). This means that △ABC will be rotated 90^(∘) about the origin O and then the image will be translated 3 units to the left and 4 units up.

Let's start by finding the coordinates of the vertices of △ ABC.

Now, we will do the transformations one at a time.

Rotation

Let's do the rotation. We will label the image △A'B'C'. For a rotation of 90^(∘) about the origin, we can find the image of each vertex by changing the sign of the y-coordinate and exchanging the x- and y-coordinates.

Preimage Change Sign of y Exchange x and y
(Image)
A( 2, 2) ( 2, -2) A'( -2, 2)
B( -1, 1) ( -1, -1) B'( -1, -1)
C( 1, -1) ( 1, 1) C'( 1, 1)
The rotation can be seen as follows.

Translation

Let's now translate △A'B'C'. We will label the image △A''B''C''. We can find the image of each vertex by subtracting3 to the x-coordinate and adding4 to the y-coordinate.

Preimage Add and Subtract Simplify
(Image)
A'(-2,2) (-2 - 3,2 + 4) A''(-5,6)
B'(-1,-1) (-1 - 3,-1 + 4) B''(-4,3)
C'(1,1) (1 - 3,1 + 4) C''(-2,5)
The translation can be seen as follows.

Final Image

Finally, we will show the preimage △ABC and the image △A''B''C'' after the rotation followed by the translation.

The vertices of △A''B''C'' are A''(-5,6), B''(-4,3), and C''(-2,5).