Question

Difficulty: EasyTransformations in the Coordinate Plane

In the standard (x,y)(x,y) coordinate plane, point PP has coordinates (3,2)(3, 2). If point PP is reflected across the yy-axis and then translated 44 units up to create point P′P', what are the coordinates of P′P'?

  1. (−3,6)(-3, 6)Answer
  2. B
    (−3,2)(-3, 2)
  3. C
    (−3,−2)(-3, -2)
  4. D
    (1,2)(1, 2)
  5. E
    (3,2)(3, 2)

Answer

The coordinates (−3,6)(-3, 6)
Reflecting the point (3,2)(3, 2) across the yy-axis changes the sign of the xx-coordinate, producing (−3,2)(-3, 2). Translating this resulting point 44 units up adds 44 to the yy-coordinate, giving the final coordinates (−3,6)(-3, 6).

Step-by-Step Solution

1
Reflect the point P(3,2)P(3, 2) across the yy-axis.
The xx-coordinate changes sign, while the yy-coordinate remains unchanged, yielding (−3,2)(-3, 2).
A reflection across the yy-axis maps any point (x,y)(x, y) to (−x,y)(-x, y).
2
Translate the point (−3,2)(-3, 2) up by 44 units.
Add 44 to the yy-coordinate: 2+4=62 + 4 = 6, yielding (−3,6)(-3, 6).
A translation of dd units upward maps any point (x,y)(x, y) to (x,y+d)(x, y + d).

Key Concept

Applying a sequence of transformations to a point in the coordinate plane by first reflecting it across an axis and then translating it.
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