The volume of a cuboid is 1440 cm³. Its height is 10 cm and the cross-section is a square. Find the side of the square.

A class room is 10 m long, 6 m broad and 4 m high. How many students can it accommodate if one student needs 1.5 m² of floor area? How many cubic metres of air will each student have?

Mary wants to decorate her Christmas tree. She wants to place the tree on a wooden box covered with coloured papers with pictures of Santa Claus. She must know the exact quantity of paper to buy for this purpose. If the box has length 80 cm, breadth 40 cm and height 20 cm respectively, then how many square sheets of paper of side 40 cm would she require?

The volume of a cuboid is 3600 cm³ and its height is 12 cm. The cross-section is a rectangle whose length and breadth are in the ratio 4 : 3. Find the perimeter of the cross-section.