Advertisements
Advertisements
प्रश्न
A rectangular strip 25 cm × 7 cm is rotated about the long side. Find The total surface area of the solid thus generated.
उत्तर
We have,
Dimension of rectangular strip = 25 cm × 7 cm
When this strip is rotated about its longer side,
The height of the cylinder becomes = 25 cm
Radius = 7 cm
∴ The total surface area of the cylinder = 2πr(h + r)
= `2 xx 22/7 xx 7(25 + 7)`
= `2 xx 22/7 xx 7 xx 32`
= 1408 cm2
APPEARS IN
संबंधित प्रश्न
It is required to make a closed cylindrical tank of height 1 m and base diameter 140 cm from a metal sheet. How many square meters of the sheet are required for the same?
`["Assume "pi=22/7]`
In a hot water heating system, there is a cylindrical pipe of length 28 m and diameter 5 cm. Find the total radiating surface in the system.
`["Assume "pi=22/7]`
Find the height of the cylinder whose volume is 1.54 m3 and diameter of the base is 140 cm?
Find the curved surface area whose height is 15 cm and the radius of the base is 7 cm.
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.
The length of a road roller is 2.1 m and its diameter is 1.4 m. For levelling a ground 500 rotations of the road roller were required. How much area of ground was levelled by the road roller? Find the cost of levelling at the rate of Rs. 7 per sq. m.
The difference between the outer and inner curved surface area of a hollow cylinder is 264 cm2. If its height is 14 cm and the volume of the material in it is 1980 cm3, find its total surface area.
The sum of the height and the radius of a cylinder is 28 cm and its total surface area is 616 cm2, find the volume of the cylinder.
The radius and height of a cylinder are in the ratio 5:7 and its curved surface area is 5500 sq.cm. Find its radius and height.
How many solid right circular cylinders of radius 2 cm and height 3 cm can be made by melting a solid right circular cylinder of diameter 12 cm and height 15 cm?
