Modelling of a bottle

Here is my first lesson.
I will describe how to make a 0.5L bottle.
At first I make calculation of volume.
A typical bottle usually consists of three solids.
The lower cylindrical part has greater volume than two other solids.
Below is the picture.

The volume of the cylinder is height*(pi*diameter^2/4).
The area of the base is in parenthesis.
The volume of the frustum is:
(pi/3)*height*(radius1^2+radius2^2+radius1*radius2)
I created a spreadsheet using LibreOffice.
The input data are the values shown on the picture above.
The output is the volume.
All dimensions are in cm.
The resulting volume is in cm^3=liter/1000.
The target volume is 500cm^3.
The are many combinations of input parameters that satisfy this target.
For example: a tall and slim bottle can have the same volume as a small and fat bottle.
I applied additional limitations.
D1=1.7cm
(This is the standard for bottle bung.)
Overall height is also limited:
h1+h2+h3=defined value.

Finally, when I have one independent variable, I am using Tools>Goal Seek to find this value for overall calculated volume =500 cm3.
The 3D model of the bottle is created in Salome-Platform.
Here is the picture of the final result.

Later I will describe all operations used for creating the geometry.
Here are the files.