Which of the following would be a line of reflection that would map ABCD onto itself?

A. [tex]x=1[/tex]
B. [tex]-x + y = 2[/tex]
C. [tex]x - y = 2[/tex]
D. [tex]2x + y = 3[/tex]



Answer :

To determine which of the given lines of reflection would map the quadrilateral ABCD onto itself, we need to understand the symmetry properties of each line.

Given four possible lines of reflection:

1. [tex]\( x = 1 \)[/tex]
2. [tex]\( -x + y = 2 \)[/tex]
3. [tex]\( x - y = 2 \)[/tex]
4. [tex]\( 2x + y = 3 \)[/tex]

### Symmetrical Analysis of Each Line

To map a quadrilateral ABCD onto itself through reflection, the line of symmetry must pass through the middle of the shape in such a way that each point and its counterpart on the opposite side are equidistant from the line.

#### Line [tex]\( x = 1 \)[/tex]

This is a vertical line at [tex]\( x = 1 \)[/tex]. Reflection over this line would swap any point [tex]\((a, b)\)[/tex] to [tex]\((2 - a, b)\)[/tex]. For this line to map the quadrilateral onto itself, the shape either has to be symmetrical about this vertical line, or every point on one side should have a corresponding point on the other side at distances that are mirror images relative to the line [tex]\( x = 1 \)[/tex].

#### Line [tex]\( -x + y = 2 \)[/tex]

This line has a slope of 1 and can be rewritten in slope-intercept form as [tex]\( y = x + 2 \)[/tex]. Reflection over this line maps any point [tex]\((a, b)\)[/tex] to another point such that the perpendicular distance to the line [tex]\( -x + y = 2 \)[/tex] is maintained. Symmetry over a line with a slope of 1 would suggest that the quadrilateral must also be aligned symmetrically in that manner.

#### Line [tex]\( x - y = 2 \)[/tex]

This line has a slope of 1 and can be rewritten as [tex]\( y = x - 2 \)[/tex]. Reflection over this line maps any point [tex]\((a, b)\)[/tex] to another point such that the perpendicular distance to the line [tex]\( x - y = 2 \)[/tex] is maintained. Again, symmetry about a line with a slope of 1 implies the quadrilateral must align symmetrically with this line.

#### Line [tex]\( 2x + y = 3 \)[/tex]

This line has a slope of -2 and can be rewritten as [tex]\( y = -2x + 3 \)[/tex]. Reflection over this line maps any point [tex]\((a, b)\)[/tex] to another point such that the perpendicular distance to the line [tex]\( 2x + y = 3 \)[/tex] is maintained. The symmetry required here would be more challenging due to the higher slope and resulting angles.

### Conclusion

Determining the correct line of reflection that maps ABCD onto itself solely through inspection or properties of lines requires knowing the coordinates of the vertices A, B, C, and D. However, if we examine the given lines for general geometric properties, typically the line of reflection for quadrilaterals symmetrically positioned would be among the simpler slopes (either 0, 1, or -1).

Given our list, vertical and 45-degree reflection lines (lines with slopes of ±1) are typical candidates. However, without specific symmetry and coordinate positions to analyze, we might consider the simplest forms. Among these lines, a vertical line [tex]\( x = 1 \)[/tex] or line with a slope of 1 appear possible candidates.

Let's conclude with a simpler and more generalized symmetry property:
From the traditional symmetry analysis of simpler geometric figures and in absence of specific coordinates, "While it truly depends on the coordinates given, absence suggests that [tex]\( x = 1 \)[/tex] is often a fundamental and easier vertical symmetry line used in reflections."

Answer: [tex]\( x = 1 \)[/tex]