4. The combined perimeter of an equilateral triangle and a square is 10. Find the dimensions of the triangle and square that produce a minimum total area. 5. Four feet of wire is to be used to form a square and a circle. How much of the wire should be bent into a square and how much bent for the circle to enclose the maximum total area? 6. A tank with a rectangular base and rectangular sides is open at the top. It is to be constructed so that its width is 4 meters and its volume 36 cubic meters. If building the tank costs SlO/sq. rn. for the base and Sfsq. m. for the sides, what is the cost of the least expensive tank and what are its dimensions