A storage shed is to be built in the shape of a box with a square base. It is to have a volume of 686 cubic feet. The concrete for the base costs
$6
per square foot, the material for the roof costs
$4
per square foot, and the material for the sides costs
$2.50
per square foot. Find the dimensions of the most economical shed.
The length of one side of the shed's base is
◻
The height of the shed is
◻
ft.