How to calculate this shape's volume So I've got this shape

How would I calculate the volume? I thought about splitting it up into a cone somehow but I don't have the rest of the information to do that, I think...What's to do?
This is not homework.
 A: 
Since the radii in your cylinder are different from one another, it can be seen as a cone with its tip cut off.
Drawing the complete cone, we notice that the tip, that has been cut off, is similar to the complete cylinder.
Naming points on the cylinder according to the picture above, similarity gives us that
$$\frac{AB}{CD} = \frac{BC+CE}{CE} \Rightarrow CE+BC=\frac{CE \cdot AB}{CD} \Rightarrow CE(1-\frac{AB}{CD}) = -BC \Rightarrow CE = \frac{BC \cdot CD}{AB-CD}$$
Using the known lengths we get
$$CE = \frac{BC \cdot CD}{AB-CD} = \frac{100 \cdot 6}{10-6} = \frac{600}{4} = 150$$
The Pythagorean theorem gives us the lengths DE and AE:
$$DE = \sqrt{CE^2-CD^2} = \sqrt{150^2-6^2} = \sqrt{22464}$$
$$AE = \sqrt{BE^2-AB^2} = \sqrt{(BC+CE)^2-AB^2} = \sqrt{250^2-10^2} = \sqrt{62400}$$ 
Now, the volume we are searching for is the volume of the tip subtracted from the volume of the entire cone. Using the formula
$$V=\frac{\pi r^2 h}{3},$$
where $r$ is the bottom radius and $h$ the height, to calculate the volume of the entire cylinder and the tip, we get that the searched for volume is
$$\frac{\pi AB^2 AE}{3}-\frac{\pi CD^2 DE}{3} = \frac{\pi 10^2 \sqrt{62400}}{3}-\frac{\pi 6^2 \sqrt{22464}}{3} = \frac{\pi}{3}(4000\sqrt{39}-864\sqrt{39}) = \frac{3136\pi\sqrt{39}}{3}$$
A: You know that the radius has shrunk by 4 meters after lenght 100 meters. It seems as though the rate of shrinking is linear. How long until $raduis = 0$? Then you can split the figure into cones.
A: This is a frustum, whose volume is
$$ V = \frac{\pi}{3} h (R^2 + r^2 + rR) = \frac{\pi}{3}100(10^2+6^2+10\times 6) = \frac{19600\pi}{3} $$
