Use the image to answer the question.

Triangle upper X upper Y upper Z and a dotted line are graphed on a coordinate plane. The x- and y-axes range from negative 7 to 7 in increments of 1. The dotted line is labeled axis of reflection and follows y equals 1.

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

(1 point)
Responses

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

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

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

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

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

Let's assume that the original coordinates of \( Z \) are given as \( (x, y) \). When reflecting a point across a horizontal line, the x-coordinate remains the same, while the y-coordinate is transformed based on its distance to the line of reflection.

  1. Determine the distance from \( Z \) to the line \( y = 1 \). If \( Z \) is at \( (x, y) \), the distance from point \( Z \) to the line \( y = 1 \) is \( |y - 1| \).

  2. The reflected point \( Z' \) will be at the same x-coordinate, with the y-coordinate calculated as follows: \[ Z' = (x, 1 - (y - 1)) = (x, 2 - y) \]

Now, if we use a specific original location for \( Z \):

  • If \( Z \) is at \( (-4, 2) \): \[ Z' = (-4, 2 - (2 - 1)) = (-4, 0) \]

Thus, the coordinates of \( Z' \) after the reflection across the line \( y = 1 \) would be \( Z'(-4, 0) \).

Therefore, the correct answer is: \[ Z′(-4, 0) \quad \text{(upper Z prime left parenthesis negative 4 comma 0 right parenthesis)} \]