Originally Posted by

**ANDS!** Yes on this account.

Drawing a diagram IS very helpful, especially when they tell you how they want the diagram to be drawn. If we have the LH to the west of A, and a point C between A and B (they tell us the best way to minimize our costs are if we run a cable underwater to the shore between A and B), we have a triangle:

We can call the hypotenuse: |LC| which is the distance from the lighthouse to the point C between A and B

We can call the base: |LA| defined as the shortest from the lighthouse to the shore, which is 4KM

We can call the side opposite the Lighthouse: |AC|, which we can label X, which is the distance from A to C, and is the POINT on the shore where our underwater cable ends

Above the Triangle LAC we have a single north-south line:

We can call the distance from B to the point C: |BC| which is the point B to C, which is the cabling for the ground - we know the maximum this length can be is 12 (not really since we are told to get a point between A and B), and that any other point would be 12-X

The next step would be to determine just what the relationships are between these sides/lines. From there, we can then form a function that gives us the cost of the underwater cable (the hypotenuse of our triangle, |LC|), and the shoreline-cable (|BC|).