Question

Point A' is the image of point A when point A is rotated about the origin B. What angle in the counterclockwise direction is

A rotated through?

Answer 1

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Answer:

90° CCW

Explanation:

The slope of BA is -1/3. The slope of BA' is 3, so the slopes are opposite reciprocals of one another. These segments are perpendicular, meaning the angle between them is 90°.

Point A' has been rotated 90° CCW about point B.