The truncated right circular cone below has a large base radius $8$ cm and a small base radius of $4$ cm. The height of the truncated cone is $10$ cm. The volume of this solid is $n \pi$ cubic cm, where $n$ is an integer. What is $n$?
The volume of a truncated cone can be calculated using the formula:
V=h3(A1+A2+√A1⋅A2),
where:
- h is the height of the truncated cone,
- A1 and A2 are the areas of the two circular bases.
In this case, the height h=10 cm, and the radii of the large and small bases are r1=8 cm and r2=4 cm respectively.
The formula for the area of a circle is A=πr2.
So, the areas of the two circular bases are:
- A1=π(82)=64π square cm,
- A2=π(42)=16π square cm.
Now, substitute the values into the formula for the volume:
V=103(64π+16π+√64π⋅16π).
Simplify inside the square root:
√64π⋅16π=128π.
Now, substitute this value back into the formula:
V=103(64π+16π+128π)=103(208π).
Simplify:
V=2080π3.
So, the value of n is 2080, and the volume of the truncated cone is 2080π cubic cm.