4. Compositions of Isometries
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A 180^(∘) rotation counterclockwise about the origin will change the coordinates of the vertices such that (a,b)→ (- a, - b).
Let's start by graphing the given coordinates so that we can see the polygon.
When a figure is rotated 180^(∘) counterclockwise about the origin, the coordinates of the vertices of the preimage will change in the following way.
| (a,b) | (- a, - b) |
|---|---|
| A(4,2) | A'(- 4,- 2) |
| B(2,8) | B'(- 2,- 8) |
| C(8,0) | C'(- 8,0) |
Knowing the vertices of â–³ A'B'C', we can draw the image.