Think of the two pieces together as a single cone of height 19, and its volume.
Then think of only the upper piece as a cone, and find its volume.
The volume of the frustum is the total volume minus the volume of the upper piece.
The volume of a cone is:

Total volume:

Volume of upper cone:

Volume of frustum:
Answer:
36.5 inches
Step-by-step explanation:
Given
See attachment for the given data
Required
Which length is closest to 4.2lb
The given data is a linear dataset.
So, we start by calculating the slope (m)

Pick any two corresponding points from the table
So, we have:


So:




The linear equation is then calculated using:

This gives:

Open bracket


To get the length closest to 4.2lb,
we set 
Then solve for x
So, we have:


Collect like terms


Solve for x

