The reflection of the plane we can use to prove d is equidistant from a and c is the reflection across line l
How to determine the line of reflection of the transformation
From the question, we have the following parameters that can be used in our computation:
Line L is the perpendicular bisector of segment AC
Also, we can see that
Both figures are in opposite sides of the line L
This means that the line of reflection must be the line that passes through the points the line L passes through
This in other words means that the line of reflection is the line L itself