Exercise 4. (8 points) The management of the UN ICO department store has decided to enclose an 800 ft2 area outside the building for displaying potted plants and owers. One side will be formed by the exter nal wall of the store, two sides will be constructed of pine boards, and the fourth side will be made of galvanized steel fencing. If the pine board fencing costs $6/running foot and the steel fencing costs $3 / running foot, determine the dimensions of the enclosure that can be erected at minimum cost