Why would we humans need to know the area of a circle -- π*r²?

So you know how to calculate the volume of your septic tank and know when to empty it out.

Let's see, this would be helpful for all kinds of engineering whether you are designing a city, a plaza, a house, a window, a CD-Player, a CD, a battery, or a tiny little cylinderical capacitor.

Not to mention, if you are a farmer and you happen to own a circular region, you would obviously want a fence around it and if you are trying to buy/sell it, you WOULD like to know how big of a piece of land are you getting.

You see, circles/spheres are the most natural shape that arise everywhere all the time. Nature loves this shape more than anything else. How many suns, planets, and moons do you know that are cubed? Atoms aren't box-like either.

Rectanlges and squares are easy to make/draw. They are easy to comprehend and pleasing to the human eye. BUT circles/spheres give us a nice symmetry like no other. So mathematicians and physicists love circles.

If you don't get good at math, you'll end up working at pizza parlour all your life. And how else are you going to calculate the amount of mozzarella that you need to cover a 9-inch, 12-inch or 15-inch pizza?

well, it can have many uses. For example, if you're going to put tiles on a perfect circle area.

Also, this may be useful if you're an engineer or an architect.

Maybe you don't realize it now, but that formula could be very helpful someday.

Well I could think of at least several dozen examples but one could be to know the area a circular pivot irrigation system covers.

I frequently use that formula and without it I would be seriously

hampered in my ability to design, calculate & engineer things..

Without this formula, you would be walking everywhere you went.

No cars..No ships...No Airplanes..No modern buildings ...Modern

society would be back to the stone age...

Good question! Better yet.. why did Einstein do E=mc(2) instead of mc(2) = E ?

the school just trained you to learned sort of things that you don't need, they trained your mind to absorb knowledge, to learn faster, and so you won't be ignorant. kids always didn't get the concept of schooling, other than the piece of hs diploma you get, school teaches us to broaden our horizons, and pick something we want in later life

Sure does help if you want to know the volume of a cylinder...

I can't speak for humans, but for us Vulcans, it is indispensable.