Question

If the height and the radius of a cone are doubled, the volume of the cone becomes
(1) 2 times
(4) 8 times
4 times
(2)
6 times
(3)​

Answer 1

❍ Let the Height and Radius of the cone be h and r respectively

=

3

1

πr

2

h

The Height and Radius of the cone are doubled. Therefore, h becomes 2h and Radius becomes 2r.

Now,

:⟹Volume

(cone)

=

3

1

πr

2

h

:⟹Volume

(cone)

=

3

1

π×(2r)

2

×2h

:⟹Volume

(cone)

=

3

1

π×4r×2h

:⟹

Volume

(cone)

=8×

3

1

πr

2

h

Totalsurfaceareaofcone=Areaofbase+CSA=πr

2

+πrl=πr(r+l)

Volumeofcone = frac{1}{3} \pi r^2 h}Volumeofcone=

3

πr

2

h