Q3. The length of the diameter of a drum made of steel covered with a lid is 28 cm. if a 2816 sq cm steel sheet is required to make the drum, let us write by calculating the height of the drum.

Q4. Let us write by calculating how many cubic decimeters of concrete material will be necessary to construct two cylindrical pillars each of whose diameter is 5:6 decimeter and height is 2.5 meter.Let us write by calculating the cost of plastering the two pillars at ₹ 125 per square meter.

Q5. If a gas cylinder for fuel purpose having the length of 7.5 dcm and the length of the inner diameter of 2.8 dcm carries 15.015 kg of gas, let us write by calculating the weight of the gas of per cubic dcm.

Q6. Out of three jars of equal diameter and height, 2/3 part of the first, 5/6 part of the second and 7/9 part of the third were filled with dilute sulphuric acid. Whole of acid in the three jars were poured into a jar of 2.1 dcm deiameter as a result the height of acid in the jar becomes 4.1 dcm. If the length of diameter of each of the three equal jars is 1.4 dcm, let us write by calculating the height of the three jars.

Q7. Total surface area of a right circular pot open at one end is 2002 sq am. If the length of diameter of base of the pot is 14 cm let us write by calculating, how much liter of water may the drum contain.

Q8. If a pump set with a pipe of 14 cm diameter can drain 2500-meter water per minute. Let us write by calculating, how much kilometer water will that pump drain per hour [1 liter = 1 cubic dcm].

Q9. There is some water in a long gas jar of 7cm diameter. If a solid right circular cylindrical pipe of iron having 5cm diameter he immersed completely in that water, let us write by calculating how much the level of water will rise.

Q10. If the surface area of a right circular cylindrical pillar is 264 sq meter and volume is 924 cubic meters. Let us write by calculating Hight and length of diameter of this pillar.

Q11. A right circular cylindrical tank of 9-meter height is filled with water. Water comes out from there through a pipe having length of 6cm diameter with a speed of 225 meter per minute and the tank becomes empty after 36 minutes, let us write by calculating the length of diameter of the tank.

Q12. Curved surface area of a right circular cylindrical log of wood of uniform density is 440 sq dcm. If 1 cubic dcm of wood weight 1.5 kg and weight of the log is 9.24 quintals. Let us write by calculating the length of diameter of log and its height.

Q13. The length of inner and outer diameter of a right circular cylindrical pipe open at two ends are 30 cm and 26 cm respectively and length of pipe is 14.7 meter. Let us write by calculating the cost of painting its all surfaces with coaltar at ₹2.25 per square dcm.

Q14. Height of a hollow right circular cylinder, open at both ends, is 2.8 meter. If length of inner diameter of the cylinder is 4.6 dcm and the cylinder is made up of 84.48 cubic dcm of iron, let us calculate the length of outer diameter of the cylinder.

Q15. Height of a right circular cylinder is twice of its radius. If the height would be 6 times of its radius then the volume of the cylinder would be greater by 539 cubic dcm, let us write by calculating the height of the cylinder.

Q16. A group of firebrigade personal carried a right circular cylindrical tank filled with water and pumped out water at a speed of 420-meter pet minute put out the fire in 40 minutes by their pipes of 2cm diameter each. If the diameter of tank is 2.8 meter and its length is 6 meters, then let us calculate

(i) What volume of water has been spent in putting out the fire and

(ii) The volume of water that still remains in the tank.

Q17. It is required to make a plastering of sand and cement with 3.5 cm thick, surrounding four cylindrical pillars, each of whose diameter is 17.5cm.

(i) If each pillar is of 3 meter height, let us write by calculating how many cubic dcm of plaster materials will be needed.

(ii) If the ratio of sand and cement in the plaster material be 4:1, let us write how many cubic dcm of cement will be needed.

Q18. The length of outer and inner diameter of hollow right circular cylinder are 16cm and 12cm respectively. Height of Cylinder is 36cm. let us calculate how many solid cylinders of 2cm diameter and 6cm length may be often by melting this cylinder.