Maths
https://drive.google.com/uc?id=1vI1e7qpn6b7MXQj0f_47E9MH_59QDDNP 1. 150 cylindrical pillars of the Delhi Metro are to be cleaned . If each pillar has a diameter of 84 cm and a height of 6 m , find the cost of cleaning the pillars at a rate of 50p per m² . 2. A rectangular sheet of paper of dimensions 44 cm x 18 cm is rolled along its length to form a cylinder . Find the total surface area of the cylinder so formed . Take it = 22 3. A cylindrical pipe is of length 28 m and diameter 5 cm . Find the total surface area of the pipe . 4. A decorative pen holder made up of cardboard is in the shape of a cylinder with a base of radius 3 cm and height 10.5 cm . Find the area of the cardboard required to make 35 decorative pen holders . 5. The curved surface area of a cylinder is 4400 cm² and the circumference of its base is 220 cm . Find the height of the cylinder . 6. Eighty equal circular dises , each 6 mm thick and radius 7 cm are placed one above the other to form a cylinder , find the total surface area of the cylinder . 7. Find the curved surface area of a garden roller whose length is 1.5 m and radius is 70 cm . How much area can it level in 200 revolutions ? 8. An open cylindrical vessel is to be made from a sheet of metal . Find the area of the metal required if the vessel has a height of 35 cm and radius of 14 cm . 9. The outer diameter of a pipe is 70 cm and has a length of 21 m . Find the cost of polishing its outer surface at the rate of 10 per m² . 10. The diameter of a 120 cm long roller is 84 cm . If it takes 1000 complete revolutions to level a playground having breadth of 36 m , find the length of the playground .