Advertisements
Advertisements
प्रश्न
Find the radius of a sphere whose surface area is 154 cm2.
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
The radius of a spherical balloon increases from 7 cm to 14 cm as air is being pumped into it. Find the ratio of surface areas of the balloon in the two cases.
Find the surface area of a sphere of diameter 21 cm .
A hemi-spherical dome of a building needs to be painted. If the circumference of the base of
the dome is 17.6 cm, find the cost of painting it, given the cost of painting is Rs. 5 per l00
`cm^2`
The volume of one sphere is 27 times that of another sphere. Calculate the ratio of their :
- radii,
- surface areas.
A hollow sphere of internal and external radii 6 cm and 8 cm respectively is melted and recast into small cones of base radius 2 cm and height 8 cm. Find the number of cones.
Find the volume of a sphere whose surface area is 154 cm2.
The radius of a sphere is 9 cm. It is melted and drawn into a wire of diameter 2 mm. Find the length of the wire in metre.
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 weight of the material drilled out if it weighs 7 gm per cm3.
There is a ratio 1: 4 between the surface area of two spheres, find the ratio between their radius.
A solid sphere is cut into two identical hemispheres.
Statement 1: The total volume of two hemispheres is equal to the volume of the original sphere.
Statement 2: The total surface area of two hemispheres together is equal to the surface area of the original sphere.
Which of the following is valid?
