Find the number of coins, 1.5 cm in diameter and 0.2 cm thick, to be melted to form a right circular cylinder with a height of 10 cm and a diameter of 4.5 cm.

How many soap cakes each measuring 7 cm 7cmx 5 cm x 2.5 cm can be placed in a box of size 56cm x 40 cm x 25 cm?

The radius and height of the cylinder are in the ratio 5 : 7 and its volume is 550 cm³. Find its radius and height.

Find the surface area of a chalk box, whose length, breadth and height are 18 cm, 10 cm and 8 cm respectively.

The curved surface area of a cylindrical pillar is 264 m² and its volume is 924 m³. Find the diameter and height of the pillar.