The Swissmill Tower in Zurich is the tallest operating grain silo in the world. Standing at 118 metres, the tower is in the shape of a rectangular box with a square base. The tower can store 45 000 m³ of grain.

(i) Estimate the length of one side the tower. Give your estimate correct to one decimal place.

(ii) There is a proposal to cover the tower's exterior with plants as it is considered too industrial looking. The cost of the planting is €250 per m². Work out the cost of covering the exterior sides of the tower with plants.​