Need help with this two part question. Below figure is used for it. Second derivative to verify results

(14) Construction A contractor would like to fence off three adjacent and equivalent rectangular areas along the side of a river. (See figure below.) Each area is to be 120 square meters. What dimensions should the contractor use in order to use the least amount of fencing, and what is the least amount of fencing? Include units. [1] (15) Cost Suppose the contractor in the previous problem decides to use a more expcInsive material for the outside fencing. They would still like to fence off three adjacent and equivalent rectangular areas of 120 In2 each along a river, as before, but the outside fencing costs $6 per meter and the inside fencing costs $4 per'meter. What dimensions should the contractor use to minimize the total cost? Include units. (See gure below.) [1]