Question

A right circular cylinder just encloses a sphere of
radius r . Find
(1)surface area of the sphere,
(2) curved surface area of the cylinder,
(3) ratio of the areas obtained in (1)and (2)​

Answer 1

Answer:

1 ) 4 * π * r² .

2) 4 * π * r².

3) 1.

Step-by-step explanation:

The radius of sphere is ' r '.

1)  Let  A =  surface area of sphere.

A = 4 * π * r² .

2)  Let  B =  curved surface area ( cylinder )

B  = 2 * π * r * h.

Here r = radius of cylinder.

h  is the height of cylinder.

Since the cylinder just encloses the sphere.

h = r + r = 2 *r.

So the curved surface area of cylinder becomes  ( B ) = 4 * π * r².

3) Ratio of area obtained in ( 1 ) and ( 2 ).

$Ratio = \frac{4 * \pi * r^{2} }{4 * \pi*r^{2} }$  = 1