If a cylinder of radius 4.3 cm and height 4.8 cm is melted and constructed into a cone of the same radius, what will be the height of this cone? (Use π=22/7)
- A28.8 cm
- B14.4 cm
- C7.2 cm
- D21.6 cm
Solution & Step-by-step Explanation
When a solid is melted and recast into another shape, its volume remains the same.
Volume of Cylinder=Volume of Cone
The formula for the volume of a cylinder is πr
2
h
1
and for a cone is
3
1
πr
2
h
2
.
Given that they have the same radius r:
πr
2
h
1
=
3
1
πr
2
h
2
We can cancel πr
2
from both sides:
h
1
=
3
1
h
2
h
2
=3×h
1
Given that the height of the cylinder h
1
=4.8 cm:
h
2
=3×4.8=14.4 cm
Thus, the height of the cone will be 14.4 cm.
Volume of Cylinder=Volume of Cone
The formula for the volume of a cylinder is πr
2
h
1
and for a cone is
3
1
πr
2
h
2
.
Given that they have the same radius r:
πr
2
h
1
=
3
1
πr
2
h
2
We can cancel πr
2
from both sides:
h
1
=
3
1
h
2
h
2
=3×h
1
Given that the height of the cylinder h
1
=4.8 cm:
h
2
=3×4.8=14.4 cm
Thus, the height of the cone will be 14.4 cm.