ganjum2671
New member
- Joined
- Mar 22, 2019
- Messages
- 8
I'm not quite sure what you are asking. If we had one cylinder, without the hollowed out part, we would have a cylinder of radius (3.5 + 0.25) in. Are you trying to confirm that?Why wouldn't we do 0.5 (diameter of the outside portion) and add that with 3.5 (radius of the inside) to find the total radius of the entire thing?
Note that this formula amounts to the same method topsquark recommended (which doesn't require memorizing a separate formula). But it doesn't deal with the bottom of the glass, which none of us have mentioned yet. It is actually for a pipe, not a hollow cylinder with a solid bottom.You can use the following formula:-
Volume of Hollow Cylinder =π*h*(R^2-r^2)
where
h=height of cylinder
R=Outer radius
r=Inner radius
Note that this formula amounts to the same method topsquark recommended (which doesn't require memorizing a separate formula). But it doesn't deal with the bottom of the glass, which none of us have mentioned yet. It is actually for a pipe, not a hollow cylinder with a solid bottom.
What you actually need to do is either to apply this formula to the part above the base and add on the entire base (a cylinder with height 0.25 in), or subtract from the volume of a cylinder with radius 3.75 and height 11.3, an inner cylinder with radius 3.5 and height 11.05. Do you see that?