If a cylinder of radius 4cm and height 8cm is melted and constructed into a cone of the same radius, what will be the height of this cone?
- A48 cm
- B24 cm
- C8 cm
- D12 cm
Solution & Step-by-step Explanation
When a solid object is melted and recast into another solid object, its volume remains the same.
Let the radius of the cylinder be r=4cm and height be h
cylinder
=8cm.
The radius of the cone is also r=4cm. Let its height be h
cone
.
Volume of Cylinder=Volume of Cone
πr
2
h
cylinder
=
3
1
πr
2
h
cone
Since the radius r is identical for both, we can cancel out πr
2
from both sides:
h
cylinder
=
3
1
h
cone
8=
3
1
h
cone
h
cone
=8×3=24cm
Let the radius of the cylinder be r=4cm and height be h
cylinder
=8cm.
The radius of the cone is also r=4cm. Let its height be h
cone
.
Volume of Cylinder=Volume of Cone
πr
2
h
cylinder
=
3
1
πr
2
h
cone
Since the radius r is identical for both, we can cancel out πr
2
from both sides:
h
cylinder
=
3
1
h
cone
8=
3
1
h
cone
h
cone
=8×3=24cm