12. A box with a square base and open top must have a volume of 32,000 cm3. Find the dimensions of the box that mini- mize the amount of material used. 27. A piece of wire 10 m long is cut into two pieces. One piece is bent into a square and the other is bent into an equilateral triangle. How should the wire be cut so that the total area enclosed is (a) a maximum? (b) A minimum? 28. A fence 8 ft tall runs parallel to a tall building at a distance of 4 ft from the building. What is the length of the shortest ladder that will reach from the ground over the fence to the wall of the building? 36. A boat leaves a dock at 2:00 PM and travels due south at a speed of 20 km/ h. Another boat has been heading due east at 15 km/h and reaches the same dock at 3:00 PM. At what time were the two boats closest together