Advertisements
Advertisements
प्रश्न
Find the radius of a sphere whose surface area is 154 cm2.
Advertisements
उत्तर
In the given problem, we have to find the radius of a sphere whose surface area is given.
Surface area of the sphere (S) = 154 cm2
Let the radius of the sphere be r cm
Now, we know that surface area of the sphere = `4pi r^2`
So,
`154=4(22/7)(r)^2`
`r^2 = ((154)(7))/((4)(22))`
`r^2 = 12.25`
Further, solving for r
`r = sqrt(12.25)`
r = 3.5
Therefore, the radius of the given sphere is 3.5 cm .
APPEARS IN
संबंधित प्रश्न
Find the radius of a sphere whose surface area is 154 cm2.
`["Assume "pi=22/7]`
A hemispherical bowl is made of steel, 0.25 cm thick. The inner radius of the bowl is 5 cm. Find the outer curved surface area of the bowl.
`["Assume "pi = 22/7]`
A certain number of metallic cones, each of radius 2 cm and height 3 cm are melted and recast into a solid sphere of radius 6 cm. Find the number of cones.
On a map drawn to a scale of 1: 50,000, a rectangular plot of land ABCD has the following dimensions. AB = 6 cm; BC = 8 cm and all angles are right angles. Find:
1) the actual length of the diagonal distance AC of the plot in km.
2) the actual area of the plot in sq. km.
Two solid spheres of radii 2 cm and 4 cm are melted and recast into a cone of height 8 cm. Find the radius of the cone so formed.
The surface area of a solid metallic sphere is 2464 cm2. It is melted and recast into solid right circular cones of radius 3.5 cm and height 7 cm. Calculate:
- the radius of the sphere.
- the number of cones recast. (Take π = `22/7`)
Find the surface area of a sphere of diameter 14 cm.
A hemispherical bowl made of brass has inner diameter 10.5 cm. Find the cost of tin- plating
it on the inside at the rate of Rs. 4 per 100 `cm^2`
A wooden toy is in the form of a cone surmounted on a hemisphere. The diameter of the base
of the cone is 16 cm and its height is 15 cm. Find the cost of painting the toy at Rs. 7 per 100
`cm^2`.
Spherical marbles of diameter 1.4 cm are dropped into beaker containing some water and are fully submerged. The diameter of the beaker is 7 cm. Find how many marbles have been dropped in it if the water rises by 5.6 cm.
The cross-section of a tunnel is a square of side 7 m surmounted by a semi-circle as shown in the adjoining figure. The tunnel is 80 m long.
Calculate:
- its volume,
- the surface area of the tunnel (excluding the floor) and
- its floor area.
Find the volume of a sphere whose surface area is 154 cm2.
Mark the correct alternative in each of the following:
In a sphere the number of faces is
The ratio of the total surface area of a sphere and a hemisphere of same radius is
A cone, a hemisphere and a cylinder stand on equal bases and have the same height. The ratio of their volumes is
The model of a building is constructed with the scale factor 1 : 30.
(i) If the height of the model is 80 cm, find the actual height of the building in meters.
(ii) If the actual volume of a tank at the top of the building is 27m3, find the volume of the tank on the top of the model.
Find the surface area and volume of sphere of the following radius. (π = 3.14)
4 cm
Find the length of the wire of diameter 4 m that can be drawn from a solid sphere of radius 9 m.
From a rectangular solid of metal 42 cm by 30 cm by 20 cm, a conical cavity of diameter 14 cm and depth 24 cm is drilled out. Find: the volume of remaining solid
The cylinder of radius 12 cm have filled the 20 cm with water. One piece of iron drop in the stands of water goes up 6.75 cm. Find the radius of sphere piece.
