Translations and Reflections
Translations are changes by directions: up, down, left, and right.
Translation Change h units to the right x changes to x + h h units to the left x changes to x - h h units up y changes to y + h h units down y changes to y - h
Reflections are changes across the x-axis or the y-axis.
Reflection Change over the y-axis x changes to -x over the x-axis y changes to -y
Example 1: Translation
Enter the coordinates of each point as an ordered pair. B is a translation of A by 9 units to the right and 13 units upward. B: (,) You find point B by translating point A by 9 units to the right and 13 units upwards. x-coordinate of point B = x-coordinate of point A + 9 = -6 + 9 = 3 y-coordinate of point B = y-coordinate of point A + 13 = -5 + 13 = 8 The answer is B: (,)
You find point B by translating point A by 9 units to the right and 13 units upwards.
x-coordinate of point B = x-coordinate of point A + 9 = -6 + 9 = 3 y-coordinate of point B = y-coordinate of point A + 13 = -5 + 13 = 8
Example 2: Translation and Reflection
Enter the coordinates of each point as an ordered pair. A is translated by 20 units to the left and 3 units downward. A is then reflected over the y-axis to get B. B: (,) This problem involves translating and then reflecting point A to get point B. Translation: Point A is translated by 20 units to the left and 3 units downward. x-coordinate of translated point A = x-coordinate of point A - 20 = 13 - 20 = -7 y-coordinate of translated point A = y-coordinate of point A - 3 = -5 - 3 = -8 The translated point A has coordinates (-7, -8). Reflection: To get point B, the translated point A is reflected over the y-axis. This means that the y-coordinate stays the same but the x-coordinate changes. x-coordinate of point B = - (x-coordinate of translated point A) = - (-7) = 7 y-coordinate of point B = y-coordinate of translated point A = - 8 The answer is B: (,)
This problem involves translating and then reflecting point A to get point B.
Translation:
Point A is translated by 20 units to the left and 3 units downward. x-coordinate of translated point A = x-coordinate of point A - 20 = 13 - 20 = -7 y-coordinate of translated point A = y-coordinate of point A - 3 = -5 - 3 = -8 The translated point A has coordinates (-7, -8).
To get point B, the translated point A is reflected over the y-axis. This means that the y-coordinate stays the same but the x-coordinate changes. x-coordinate of point B = - (x-coordinate of translated point A) = - (-7) = 7 y-coordinate of point B = y-coordinate of translated point A = - 8
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