Sumy is working in geometry class and is given figure [tex]$ABCD$[/tex] in the coordinate plane to reflect. The coordinates of point [tex]$D$[/tex] are [tex]$(a, b)$[/tex], and she reflects the figure over the line [tex]$y = x$[/tex]. What are the coordinates of the image [tex]$D^{\prime}$[/tex]?

A. [tex]$(a, -b)$[/tex]
B. [tex]$(b, a)$[/tex]
C. [tex]$(-a, b)$[/tex]
D. [tex]$(-b, -a)$[/tex]



Answer :

To determine the coordinates of the image [tex]\( D^{\prime} \)[/tex] when point [tex]\( D \)[/tex] with coordinates [tex]\( (a, b) \)[/tex] is reflected over the line [tex]\( y = x \)[/tex], follow these steps:

1. Understand that reflecting a point over the line [tex]\( y = x \)[/tex] swaps its x-coordinate with its y-coordinate. Therefore,:
- The original coordinates of [tex]\( D \)[/tex] are [tex]\( (a, b) \)[/tex].
- After reflecting over the line [tex]\( y = x \)[/tex], the new coordinates [tex]\( D' \)[/tex] will be [tex]\( (b, a) \)[/tex].

Given this reflection rule, the coordinates of the image [tex]\( D^{\prime} \)[/tex] are [tex]\( (b, a) \)[/tex].

Thus, the correct answer is:
[tex]\[ (b, a) \][/tex]