The height of a cone is 30cm. A small cone is cut off at the top by a plane parallel to the base. What if its volume is 1/27 of the given cone?
Let's denote the height of the small cone as 'h' and its radius as 'r'.
The given cone has a height of 30cm, so its volume can be calculated using the formula:
V1 = (1/3)πr^2h1
where h1 = 30cm is the height of the given cone.
Now, the small cone is cut off at the top by a plane parallel to the base. This means that the top portion of the given cone and the small cone are similar in shape.
Since the volume of the small cone is 1/27 of the given cone, we can write:
V2 = (1/3)πr^2h2 = (1/27)V1
where h2 = 30 - h is the height of the small cone.
We can simplify the above equation to get:
h2/h1 = (1/3)^(1/3)
Using this ratio, we can find the height of the small cone:
h2 = (1/3)^(1/3) * h1 = (1/3)^(1/3) * 30 ≈ 16.18 cm
Now that we know the height of the small cone, we can use the ratio of the heights to find the radius of the small cone:
h2/h1 = r2/r1
r2 = (h2/h1) * r1 = (16.18/30) * r1 ≈ 8.73 cm
Finally, we can calculate the volume of the small cone using the formula:
V2 = (1/3)πr^2h2 ≈ 508.94 cubic cm
Comments
Post a Comment