Question

If the radius of the circular base of a right circular cone is tripled, find the ratio of the volume of the first
one to that of the second, the height remaining same.​

Answer 1

Answer:

Suppose that

Radius of the base is r, and the height of the original cone is h.

Then,

Volume of the original cone (V

1

)=

3

1

πr

2

h

When cone reduced then,

radius =

2

r

height =h

Now,

Volume of the reduced cone (V

2

)=

3

1

π(

2

r

)

2

h

=

4

1

(

3

1

πr

2

h)

=

4

1

V

1

$$

∴

V

1

V

2

=

4

1

=1:4