Two isolated farms are situated 10 km apart on a straight road. The road runs parallel to a highway that is 20 km away. A power company decides to run a wire from the highway to a junction box, and from there, it will run two separate wires of equal length to the two farms. Find the distance from the highway that the junction box should be placed to minimize the length of the wire needed?

A) Diagram modelling the question. - diagram attached

B) State the restriction on the variable(s)

C) Indicate the equation to be optimized.

D) Indicate the derivative and the complete solution - Ans: 17.11km

* I am having trouble mainly with finding the derivative