Advertisements
Advertisements
प्रश्न
The radii of two cylinders are in the ratio 3 : 5 and their heights are in the ratio 2 : 3. What is the ratio of their curved surface areas?
उत्तर
Given that, `r_1 :r_2 = 3:5 " and " h_1 : h_2 = 2 : 3`
Now, the ratio of their curved surface area
`s_1 :s_2 = 2pir_1h_1 : 2 pir_2h_2`
`s_1 :s_2 = 2pir_1 h_1 : 2pir_2 h_2`
`(s_1)/s_2 = (2pir_1h_2)/(2pir_2h_2)`
`=(r_1 /r_2) (h_1/h_2)`
`(s_1)/s_2 = 3/5 xx 2/3 = 2/5`
Hence , `s_1 :s_2 = 2 : 5`
APPEARS IN
संबंधित प्रश्न
A conical vessel, with base radius 5 cm and height 24 cm, is full of water. This water is emptied into a cylindrical vessel of base radius 10 cm. Find the height to which the water will rise in the cylindrical vessel. (use `pi=22/7`)
In one fortnight of a given month, there was a rainfall of 10 cm in a river valley. If the area of the valley is 7280 km2, show that the total rainfall was approximately equivalent to the addition to the normal water of three rivers each 1072 km long, 75 m wide and 3 m deep.
A solid sphere of radius 10.5 cm is melted and recast into smaller solid cones, each of radius 3.5 cm and height 3 cm.Find the number of cones so formed.
Find the volume of a cone if the radius of its base is 1.5 cm and its perpendicular height is 5 cm.
Find the ratio of the volumes of a cylinder and a cone having equal radius and equal height.
(A)1 : 2 (B) 2 : 1 (C) 1 : 3 (D) 3 : 1
The surface area of a sphere is 2464 cm2. If its radius be doubled, then what will be the surface area of the new sphere?
The diameter of a sphere is 42 cm. It is melted and drawn into a cylindrical wire of diameter 2.8 cm. Find the length of the wire.
The diameter of a cylinder is 28 cm and its height is 20 cm. The total surface area of the cylinder is
The radius of the base of a cone is 5 cm and its height is 12 cm. Its curved surface area is
Find the surface area of a sphere of radius 7 cm.
Solution :
The surface area of the sphere = 4πr2
= `4 xx 22/7 xx square^2`
= `4 xx 22/7 xx square`
= `square xx 7`
∴ The surface area of the sphere = `square` sq.cm.
