Practice | Hashtable

1. The ratio of the surface area of a sphere and the curved surface area of the cylinder circumscribing the sphere is :

A. 1 : 1

B. 1 : 2

C. 2 : 1

D. 2 : 3

Solution:

Let the radius of the sphere be r
Then, radius of the cylinder = r
Height of the cylinder = 2r
Surface area of sphere =

4 π r^{2}

Surface area of the cylinder =

2 π r (2 r) = 4 π r^{2}

∴ Required ratio :
=

4 π r^{2}

4 π r^{2}

= 1 : 1

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