Answer: Liz is further away. Her distance from Robert is 5 units.
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Work Shown:
R = Robert's location = (4,3)
L = Lucy's location = (6,1)
Z = Liz's location = (1,7)
We need to find the lengths of segments RL and RZ to find out which person (Lucy or Liz) is further from Robert.
Use the distance formula to find the length of each segment. Let's start with the distance from R to L
[tex]d = \sqrt{(x_1+x_2)^2+(y_1+y_2)^2}\\\\d = \sqrt{(4-6)^2+(3-1)^2}\\\\d = \sqrt{8}\\\\d \approx 2.828427\\\\[/tex]
The distance from Robert to Lucy is approximately 2.828427 units.
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Now find the distance from R to Z
[tex]d = \sqrt{(x_1+x_2)^2+(y_1+y_2)^2}\\\\d = \sqrt{(4-1)^2+(3-7)^2}\\\\d = \sqrt{25}\\\\d = 5\\\\[/tex]
The distance from Robert to Liz is exactly 5 units. We see that Liz is further away from Robert, compared to Lucy's distance from him.