9514 1404 393
Answer:
180°
Explanation:
When you look at the coordinates, you see that each one has been negated. That is, the image point is in the quadrant opposite the one the preimage point is in.
Every point and its image on a rotated figure makes an angle with the center of rotation that is equal to the angle of rotation. When the preimage and image points are in opposite (not adjacent) quadrants, that angle is 180°.
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Additional comment
It can be helpful to learn to recognize certain transformations. A rotation of 90° will swap the coordinates and negate one of them. A rotation of 180° negates both coordinates without swapping them.