Segment [tex]$AB$[/tex] is on the line [tex]$y - 4 = -5(x - 1)$[/tex], and segment [tex]$CD$[/tex] is on the line [tex]$y - 4 = \frac{1}{5}(x - 5)$[/tex]. Which statement proves the relationship of segments [tex]$AB$[/tex] and [tex]$CD$[/tex]?

A. They are perpendicular because they have slopes that are opposite reciprocals of 5 and [tex]$-\frac{1}{5}$[/tex].
B. They are perpendicular because they have slopes that are opposite reciprocals of -5 and [tex]$\frac{1}{5}$[/tex].
C. They are parallel because they have the same slope of 5.
D. They are parallel because they have the same slope of [tex]$-\frac{1}{5}$[/tex].



Answer :

To determine the relationship between segments [tex]\(A B\)[/tex] and [tex]\(C D\)[/tex], we need to analyze the slopes of the lines on which these segments lie.

1. Equation of segment [tex]\(A B\)[/tex]:
The given equation is [tex]\(y - 4 = -5(x - 1)\)[/tex].

To find the slope, we rewrite this equation in the slope-intercept form [tex]\(y = mx + b\)[/tex].

[tex]\[ y - 4 = -5(x - 1) \][/tex]

Distribute [tex]\( -5 \)[/tex] on the right-hand side:

[tex]\[ y - 4 = -5x + 5 \][/tex]

Add 4 to both sides to solve for [tex]\( y \)[/tex]:

[tex]\[ y = -5x + 9 \][/tex]

From this equation, the slope [tex]\( m \)[/tex] of segment [tex]\( A B \)[/tex] is [tex]\( -5 \)[/tex].

2. Equation of segment [tex]\(C D\)[/tex]:
The given equation is [tex]\(y - 4 = \frac{1}{5}(x - 5)\)[/tex].

To find the slope, we rewrite this equation in the slope-intercept form [tex]\(y = mx + b\)[/tex].

[tex]\[ y - 4 = \frac{1}{5}(x - 5) \][/tex]

Distribute [tex]\( \frac{1}{5} \)[/tex] on the right-hand side:

[tex]\[ y - 4 = \frac{1}{5}x - 1 \][/tex]

Add 4 to both sides to solve for [tex]\( y \)[/tex]:

[tex]\[ y = \frac{1}{5}x + 3 \][/tex]

From this equation, the slope [tex]\( m \)[/tex] of segment [tex]\( C D \)[/tex] is [tex]\( \frac{1}{5} \)[/tex].

3. Analyzing the slopes:
- The slope of segment [tex]\( A B \)[/tex] is [tex]\( -5 \)[/tex].
- The slope of segment [tex]\( C D \)[/tex] is [tex]\( \frac{1}{5} \)[/tex].

Two lines are perpendicular if the product of their slopes is [tex]\( -1 \)[/tex]. That is, if the slopes [tex]\( m_1 \)[/tex] and [tex]\( m_2 \)[/tex] satisfy [tex]\( m_1 \cdot m_2 = -1 \)[/tex].

Let's check the product of the slopes:

[tex]\[ -5 \cdot \frac{1}{5} = -1 \][/tex]

Since the product of their slopes is [tex]\( -1 \)[/tex], the lines are perpendicular.

Based on this, the correct statement that proves the relationship of segments [tex]\( A B \)[/tex] and [tex]\( C D \)[/tex] is:

They are perpendicular because they have slopes that are opposite reciprocals of -5 and [tex]\( \frac{1}{5} \)[/tex].

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