Question

If the height and radius of a cone of volume V are doubled, then the volume of the
cone, is
(a) 3V
(b) 4V
(c) 6V
(d) 8V​

Answer 1

Answer:

Let radius of cone be r and height of cone be h.

so volume of cone, v =

$\frac{1}{3} \pi \: {r}^{2} h$

Now

Radius = 2r

Height = 2h

So volume, V =

$\frac{1}{3} \pi \: {(2r)}^{2} (2h) \\ = 8 \times \frac{1}{3} \pi \: {r}^{2} h \\ = 8v$

So option (d) is correct

Answer 2

Answer:

option d 8V

volume of cone is equal to 1/3πr^2h

V' =1/3π (2r)^2×2h

V'=8×1/3 πr^2 h

V' =8V