RD Sharma Class 9 Solutions Chapter 21 VSAQS (Updated 2021-22)

RD Sharma Class 9 Solutions Chapter 21 VSAQS: You can download RD Sharma Solutions Class 9 Maths Chapter 21 Surface Area And Volume of Sphere VSAQS. These solutions are created by our experts. They provided very helpful answers for your level 9 exam. The problem was resolved in an organized manner. These solutions can be used for free PDF forms that can be easily stored for long periods of time.

• RD Sharma Class 9 Maths Solutions

Access RD Sharma Class 9 Solutions Chapter 21 VSAQS

Question 1.
Find the surface area of a sphere of radius 14 cm.
Solution:
Radius of a sphere (r) = 14 cm
∴ Surface area = 4πr² = 4 x 227 x 14 x 14 cm²
= 2464 cm³

Question 2.
Find the total surface afea of a hemisphere of radius 10 cm.
Solution:
Radius of hemisphere (r) = 10 cm
∴ Total surface area = 3πr²

Question 3.
Find the radius of a sphere whose surface area is 154 cm².
Solution:
Surface area of a sphere = 154 cm²

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 cm².
Solution:
Surface area of a sphere = 154 cm²

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 = a² = (44)² cm²
= 44 × 44 × 44 cm³
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 = 42 = 2 cm
Similarly the outer radius (R) = 82 = 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 = 4πr²
= 4π x 5 x 5 = 100π cm²
Radius of cone (r₁) = 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 = a³
∵ A sphere is inscribed in the cube
∴ Diameter of sphere = a

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