Answer: 1.2704 ohm
Step-by-step explanation:
Since resistance is directly proportional to the length of the conductor.
Let x be the resistance of the same conductor at 800 feet.
Then by direct proportion,
[tex]\frac{x}{800}=\frac{0.397}{250}\\\Rightarrow\ x=\frac{0.397\times800}{250}\\\Rightarrow\ x=1.2704[/tex]
hence, the resistance of same conductor at 800 feet = 1.2704 ohm