I am not a mathematician or an engineer...

That said, if you have two flower pots, both of which are the same height and made from the same material, and both are 4" tall...

BUT

...one is round, and one is square, the square pot holds more (water/soil/air), right?

How do you determine exactly how much more?

This is not a homework question (I'm 32 years old, lol), I am just trying to do some planning for my little primroses.

My math is strictly for "Dummies", but ... fill each pot, measuring as you go. If a 4" square pot takes 2 1/2 cups of mix and the round takes 2 cups you have a 5:4 ratio (this may all be wrong but it always works for me). So if you increase the size of the pot to 12 inch, you increase it 3 times, and 3x5 = 15 cups of soil. 3x4 = 12 cups. Or not. I use this little formula for everything and it mostly works with an adjustment here and there.

The pots don't exist (yet) so they can't be filled. The "problem" is theoretical in trying to figure it out. lol

Jai_Ganesha said: ...both are 4" tall...

I just finished buying a case of pots...
We need more information than just the height of each pot. Along with the height of 4" you have to know the diameter at the top of the round pot and the measurement at the top of the square pot.

You can download the catalog for East Jordan Plastics. In the catalog you will find the height, diameter, volume/capacity, etc.

Hope this helps.