Use the image to determine the direction and angle of rotation.

Graph of polygon ABCD in quadrant 2 with point A at negative 8 comma 12. A second polygon A prime B prime C prime D prime in quadrant 3 with point A prime at negative 12 comma negative 8.
90° clockwise rotation
90° counterclockwise rotation
180° counterclockwise rotation
270° counterclockwise rotation

1 answer

To determine the direction and angle of rotation from polygon ABCD to polygon A'B'C'D', we need to analyze the coordinates of points A and A'.

Point A: (-8, 12)
Point A': (-12, -8)

Step 1: Analyze the Transformation

  • The original point A is located in quadrant 2, where x is negative and y is positive.
  • The transformed point A' is in quadrant 3, where both x and y are negative.

Step 2: Determine the Rotation

We can find how the coordinates change when rotated around the origin:

  • A 90° clockwise rotation would transform the point (x, y) into (y, -x).
  • A 90° counterclockwise rotation would transform the point (x, y) into (-y, x).
  • A 180° rotation would transform the point (x, y) into (-x, -y).
  • A 270° counterclockwise rotation is equivalent to a 90° clockwise rotation, as it effectively rotates the point back by 90°.

Step 3: Calculate the Transformations

Let's see if A = (-8, 12) can yield (-12, -8) through any of these transformations:

  1. 90° Clockwise Transformation:

    \[ (x, y) \to (y, -x) \Rightarrow (-8, 12) \to (12, 8) \]

    This does not yield A'.

  2. 90° Counterclockwise Transformation:

    \[ (x, y) \to (-y, x) \Rightarrow (-8, 12) \to (-12, -8) \]

    This transformation gives us A', which matches.

  3. 180° Counterclockwise Transformation:

    \[ (x, y) \to (-x, -y) \Rightarrow (-8, 12) \to (8, -12) \]

    This does not yield A'.

  4. 270° Counterclockwise Transformation:

    A 270° counterclockwise is the same as a 90° clockwise. Therefore, this does not apply.

Conclusion

The transformation from point A to point A' is a 90° counterclockwise rotation.