English Medium Class 9 - CBSE Question Bank Solutions for Mathematics

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 hollow sphere, in which the circus motor cyclist performs his stunts, has a diameter of 7 m. Find the area available to the motorcyclist for riding.

How many spherical bullets can be made out of a solid cube of lead whose edge measures 44 cm, each bullet being 4 cm in diameter?

If a sphere of radius 2r has the same volume as that of a cone with circular base of radius r, then find the height of the cone.

If a hollow sphere of internal and external diameters 4 cm and 8 cm respectively melted into a cone of base diameter 8 cm, then find the height of the cone.

If a sphere is inscribed in a cube, find the ratio of the volume of cube to the volume of the sphere.

Mark the correct alternative in each of the following:
In a sphere the number of faces is 

The total surface area of a hemisphere of radius r is

The ratio of the total surface area of a sphere and a hemisphere of same radius is

A sphere and a cube are of the same height. The ratio of their volumes is 

The largest sphere is cut off from a cube of side 6 cm. The volume of the sphere will be

A cylindrical rod whose height is 8 times of its radius is melted and recast into spherical balls of same radius. The number of balls will be

If the ratio of volumes of two spheres is 1 : 8, then the ratio of their surface areas is 

If the surface area of a sphere is 144π m², then its volume (in m³) is 

If a solid sphere of radius 10 cm is moulded into 8 spherical solid balls of equal radius, then the surface area of each ball (in sq.cm) is

If a sphere is inscribed in a cube, then the ratio of the volume of the sphere to the volume of the cube is