Determine the image coordinates of point [tex]\( K \)[/tex] after reflection across the line [tex]\( y = -4 \)[/tex].

Given:
- Polygon [tex]\( JKLM \)[/tex] with vertices [tex]\( J (-4, -3) \)[/tex], [tex]\( K (-4, -6) \)[/tex], [tex]\( L (-1, -6) \)[/tex], [tex]\( M (-1, -3) \)[/tex].

Options:
A. [tex]\( K' (-4, -4) \)[/tex]
B. [tex]\( K' (4, -6) \)[/tex]
C. [tex]\( K' (-4, 6) \)[/tex]
D. [tex]\( K' (-4, -2) \)[/tex]



Answer :

To determine the image coordinates of point [tex]\(K\)[/tex] when reflected across the line [tex]\(y = -4\)[/tex], we need to follow a specific method for reflections. Let's go through the steps:

1. Identify the coordinates of point [tex]\(K\)[/tex]:
[tex]\(K(-4, -6)\)[/tex]

2. Understand the reflection concept:
When a point [tex]\((x, y)\)[/tex] is reflected across the line [tex]\(y = c\)[/tex], the new y-coordinate, [tex]\(y'\)[/tex], of the reflected point can be determined using the formula:
[tex]\[ y' = 2c - y \][/tex]
where [tex]\(c\)[/tex] is the y-coordinate of the line of reflection.

3. Plug in the known values:
- For the line [tex]\(y = -4\)[/tex], [tex]\(c = -4\)[/tex].
- The y-coordinate of [tex]\(K\)[/tex] is [tex]\(-6\)[/tex].

4. Calculate the new y-coordinate [tex]\(y'\)[/tex]:
[tex]\[ y' = 2(-4) - (-6) = -8 + 6 = -2 \][/tex]

5. The x-coordinate remains the same during a vertical reflection:
Therefore, the x-coordinate of [tex]\(K'\)[/tex] is still [tex]\(-4\)[/tex].

6. Combine the new coordinates:
Hence, the coordinates of [tex]\(K'\)[/tex] after reflection across the line [tex]\(y = -4\)[/tex] are:
[tex]\[ K'(-4, -2) \][/tex]

7. Choose the correct multiple-choice answer:
The correct image coordinate for [tex]\(K'\)[/tex] is:
[tex]\[ K'(-4, -2) \][/tex]

Thus, the correct answer is:
[tex]\[ \boxed{K^{\prime}(-4, -2)} \][/tex]

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