Select the correct answer.

Point [tex]$R$[/tex] divides [tex]$\overline{EF}$[/tex] in the ratio [tex]$1:5$[/tex]. If the coordinates of [tex]$E$[/tex] and [tex]$F$[/tex] are [tex]$(4,8)$[/tex] and [tex]$(11,4)$[/tex], respectively, what are the coordinates of [tex]$R$[/tex] to two decimal places?

A. [tex]$(4.66, 7.62)$[/tex]
B. [tex]$(6, 6.86)$[/tex]
C. [tex]$(5.17, 7.33)$[/tex]
D. [tex]$(9.83, 4.67)$[/tex]



Answer :

To determine the coordinates of point [tex]\( R \)[/tex] which divides the line segment [tex]\( \overline{EF} \)[/tex] in the ratio [tex]\( 1:5 \)[/tex], we can use the section formula. The section formula for a point dividing a line segment in a given ratio [tex]\( m:n \)[/tex] is:

[tex]\[ R\left( \frac{m \cdot F_x + n \cdot E_x}{m + n}, \frac{m \cdot F_y + n \cdot E_y}{m + n} \right) \][/tex]

Here, the coordinates of points [tex]\( E \)[/tex] and [tex]\( F \)[/tex] are given as:
[tex]\[ E(x_1, y_1) = (4, 8) \][/tex]
[tex]\[ F(x_2, y_2) = (11, 4) \][/tex]

The ratio [tex]\( m:n \)[/tex] is given as [tex]\( 1:5 \)[/tex], meaning [tex]\( m = 1 \)[/tex] and [tex]\( n = 5 \)[/tex].

Let's calculate the coordinates of [tex]\( R \)[/tex]:

1. Calculate the [tex]\( x \)[/tex]-coordinate of [tex]\( R \)[/tex]:
[tex]\[ R_x = \frac{m \cdot F_x + n \cdot E_x}{m + n} = \frac{1 \cdot 11 + 5 \cdot 4}{1 + 5} \][/tex]

Breaking it down step by step:
[tex]\[ R_x = \frac{11 + 20}{6} = \frac{31}{6} \approx 5.17 \][/tex]

2. Calculate the [tex]\( y \)[/tex]-coordinate of [tex]\( R \)[/tex]:
[tex]\[ R_y = \frac{m \cdot F_y + n \cdot E_y}{m + n} = \frac{1 \cdot 4 + 5 \cdot 8}{1 + 5} \][/tex]

Breaking it down step by step:
[tex]\[ R_y = \frac{4 + 40}{6} = \frac{44}{6} \approx 7.33 \][/tex]

After performing these calculations, we find the coordinates of point [tex]\( R \)[/tex] to be approximately [tex]\( (5.17, 7.33) \)[/tex].

Thus, the correct answer is:
C. [tex]\( (5.17, 7.33) \)[/tex]