Big Ideas Math Integrated I, 2016
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Big Ideas Math Integrated I, 2016 View details
3. Rotations
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Exercise 16 Page 567

If a point, (a,b), is reflected in the x-axis, then its image is the point (a,- b).

Practice makes perfect

Let's begin by drawing △ LMN.

When a figure is reflected in the x-axis, the coordinates of its vertices will change in the following way. preimage (a,b)→ image (a,- b)

Using this rule on the vertices of △ LMN, we can find the coordinates of the reflected figure.

Point (a,b) (a,- b)
L (1,6) (1,- 6)
M (- 2,4) (- 2,- 4)
N (3,2) (3,- 2)

Now we can draw △ L'M'N'.

The second transformation is a rotation by 270^(∘) counterclockwise about the origin. There is also a rule for how the coordinates of the image will change. preimage (a,b)→ image (b,- a) Using this rule on the endpoints of △ L'M'N', we can find the vertices of △ L''M''N''.

Point (a,b) (b,- a)
L' (1,- 6) (- 6,- 1)
M' (- 2,- 4) (- 4,2)
N' (3,- 2) (- 2,- 3)

Now we can draw △ L''M''N''.

Finally, we will remove △ L'M'N' from the diagram.