Question

Find the co-ordinates of the image of $A(-5,4)$ after reflection in the line.

(ii) $y=4$

Answer 1

Given point: $A(-5,4)$

Let the image be $A^{\prime }$.

Mark $A(-5,4)$ on the graph. Draw a line $y=4$.

The image of point $A$ about a line $y=4$ is a point $A^{\prime }$ on the other side of the line such that $A^{\prime }$ is at the same distance from line as point $A$ is from it.

The line $y=4$ passes through $A$.

So, the distance between the line and $A$ is $0$.


Hence, the co-ordinates of the image of the given point after reflection in the line $y=4\text{are}(-5,4)$.