Advertisements
Advertisements
Question
Find
How much steel was actually used, if `1/12` of the steel actually used was wasted in making the tank.
`["Assume "pi=22/7]`
Solution
Total surface area of tank = 2πr (r + h)
`=[2xx22/7xx(2.1+4.5)]m^2`
= (44 × 0.3 × 6.6) m2
= 87.12 m2
Let A m2 steel sheet be actually used in making the tank.
`therefore(1-1/12)=87.12m^2`
`rArr A=(12/11xx87.12)m^2`
⇒ A = 95.04 m2
Therefore, 95.04 m2 steel was used in actual while making such a tank.
APPEARS IN
RELATED QUESTIONS
In the given figure, you see the frame of a lampshade. It is to be covered with a decorative cloth. The frame has a base diameter of 20 cm and height of 30 cm. A margin of 2.5 cm is to be given for folding it over the top and bottom of the frame. Find how much cloth is required for covering the lampshade.
`["Assume "pi=22/7]`
Find the volume of a cylinder whose r = 2.8 m, h = 15 m .
The ratio between the radius of the base and the height of a cylinder is 2 : 3. Find the total surface area of the cylinder, if its volume is 1617 cm3.
The height of a right circular cylinder is 10.5 m. Three times the sum of the areas of its two circular faces is twice the area of the curved surface. Find the volume of the cylinder.
How many cubic metres of earth must be dug-out to sink a well 21 m deep and 6 m diameter?
The curved surface area of a cylindrical pillar is 264 m2 and its volume is 924 m3. Find the diameter and the height of the pillar.
Two circular cylinders of equal volumes have their heights in the ratio 1 : 2. Find the ratio of their radii.
Find the length of 13.2 kg of copper wire of diameter 4 mm, when 1 cubic cm of copper weighs 8.4 gm.
Find the area to be painted in the following block with a cylindrical hole. Given that length is 15 cm, width 12 cm, height 20 cm and radius of the hole 2.8 cm.
In the example given below, the radius of the base of a cylinder and its height is given. Then find the curved surface area and total surface area.
r = 1.4 cm, h = 2.1 cm
