An agricultural field is in the form of a rectangle having length x₁ meters and breadth x₂ meters (x₁ and x₂ are variable). If x₁ + x₂ = 40 meters, then the area of the agricultural field will not exceed which one of the following values?

AB is vertical trunk of huge tree with A being the point where base of trunk touches the ground. Due to a cyclone, the trunk has been broken at C which is at height of 12 meters, broken part is partially attached to vertical portion of trunk at C. If the end of broken part B touches the ground at D which is at distance of 5 meters from A, then the original height of trunk is:

A piece of tin is in the form of rectangle having length 12 cm and width 08 cm. This is used to construct a closed cube. The side of the cube is:

A cylindrical overhead tank of radius 2m and height 7m is to be filled from an underground tank of size 5.5m×4m×6m. How much portion of the underground tank is still filled with water after filling the overhead tank completely?