## RD Sharma Class 9 Solutions Chapter 21 Surface Areas and Volume of a Sphere VSAQS

These Solutions are part of RD Sharma Class 9 Solutions. Here we have given RD Sharma Class 9 Solutions Chapter 21 Surface Areas and Volume of a Sphere VSAQS

Other Exercises

- RD Sharma Class 9 Solutions Chapter 21 Surface Areas and Volume of a Sphere Ex 21.1
- RD Sharma Class 9 Solutions Chapter 21 Surface Areas and Volume of a Sphere Ex 21.2
- RD Sharma Class 9 Solutions Chapter 21 Surface Areas and Volume of a Sphere VSAQS
- RD Sharma Class 9 Solutions Chapter 21 Surface Areas and Volume of a Sphere MCQS

Question 1.

Find the surface area of a sphere of radius 14 cm.

Solution:

Radius of a sphere (r) = 14 cm

∴ Surface area = 4πr^{2} = 4 x \(\frac { 22 }{ 7 }\) x 14 x 14 cm^{2}

= 2464 cm^{3}

Question 2.

Find the total surface afea of a hemisphere of radius 10 cm.

Solution:

Radius of hemisphere (r) = 10 cm

∴ Total surface area = 3πr^{2}

Question 3.

Find the radius of a sphere whose surface area is 154 cm^{2}.

Solution:

Surface area of a sphere = 154 cm^{2}

Question 4.

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

Solution:

Diameter of hollow sphere = 7 m

Question 5.

Find the volume of a sphere whose surface area is 154 cm^{2}.

Solution:

Surface area of a sphere = 154 cm^{2}

Question 6.

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?

Solution:

Edge of a solid cube = 44 cm

∴ Volume = a^{2} = (44)^{2} cm^{2}

= 44 × 44 × 44 cm^{3}

Diameter of a spherical bullet = 4 cm

Question 7.

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.

Solution:

Radius of a sphere (R) = 2r

Question 8.

If a hollow sphere of intefnal 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.

Solution:

Internal diameter of a hollow sphere = 4cm

∴ Internal radius = \(\frac { 4 }{ 2 }\) = 2 cm

Similarly the outer radius (R) = \(\frac { 8 }{ 2 }\) = 4 cm

∴ Volume of melted used in hollow sphere

Question 9.

The surface area of a sphere of radius 5 cm is five times the area of the curved surface of a cone of radius 4 cm. Find the height of the cone.

Solution:

Radius of a sphere (r) = 5 cm

∴ Surface area = 4πr^{2}

= 4π x 5 x 5 = 100π cm^{2}

Radius of cone (r_{1}) = 4 cm

Question 10.

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

Solution:

Let edge of a cube = a

Then its volume = a^{3}

∵ A sphere is inscribed in the cube

∴ Diameter of sphere = a

Hope given RD Sharma Class 9 Solutions Chapter 21 Surface Areas and Volume of a Sphere VSAQS are helpful to complete your math homework.

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