Find the coordinates of Z′ after a reflection across y=1.

(1 point)
Responses

Z′(−4,0)
upper Z prime left parenthesis negative 4 comma 0 right parenthesis

Z′(−4,2)
upper Z prime left parenthesis negative 4 comma 2 right parenthesis

Z′(6,2)
upper Z prime left parenthesis 6 comma 2 right parenthesis

Z′(4,0)
upper Z prime left parenthesis 4 comma 0 right parenthesis

1 answer

To find the coordinates of point \( Z' \) after reflection across the line \( y = 1 \), we need to know the original coordinates of point \( Z \).

However, if we assume \( Z \) has some coordinates \( (x, y) \), the reflection across the line \( y = 1 \) will maintain the x-coordinate, while the y-coordinate will change. The formula for the reflection across the horizontal line is given by the following:

\[ y' = 2k - y \]

where \( k \) is the y-value of the line of reflection (in this case, \( k = 1 \)).

Therefore, the new y-coordinate after reflection would be:

\[ y' = 2(1) - y = 2 - y \]

Now, we need to analyze the given response options to see which one could work based on common reflection results.

Test Each Response

  1. For \( Z′(−4, 0) \): \[ y' = 2 - 0 = 2 \quad \text{(not a match)} \]

  2. For \( Z′(−4, 2) \): \[ y' = 2 - 2 = 0 \quad \text{(not a match)} \]

  3. For \( Z′(6, 2) \): \[ y' = 2 - 2 = 0 \quad \text{(not a match)} \]

  4. For \( Z′(4, 0) \): \[ y' = 2 - 0 = 2 \quad \text{(matches \( y′ = 2 \))} \]

So the only point that after reflection across \( y = 1 \) gives the correct new coordinates is:

Answer:

\( Z′(4, 2) \)