RD Sharma - Mathematics

Book: RD Sharma - Mathematics

Chapter: 21. Surface Area and Volume of a Sphere

Subject: Mathematics - Class 9th

Q. No. 20 of Exercise 21.2

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20

The radius of the internal and external surfaces of a hollow spherical shell are 3 cm and 5 cm respectively. If it is melted and recast into a solid cylinder of height cm. Find the diameter of the cylinder.

Volume of a sphere = (4/3)πr3


Volume of a cylinder = πr2h


Given, radius of the internal and external surfaces of a hollow spherical shell are 3 cm and 5 cm respectively. It is melted and recast into a solid cylinder of height cm.


Volume of material = Volume of the solid cylinder



r2 = 49


r = 7 cm


Diameter = 14 cm


20

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