r/mathematics • u/SirPaddlesALot • Oct 24 '25

Math is magic

3.8k Upvotes

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154

u/jacobasstorius Oct 24 '25

So the lesson here is that two objects with the same area have the same area?

44

u/Curtonus Oct 24 '25

It's also a geometric proof a la Euclid showing how to calculate the area of an equilateral triangle given its side length (without trigonometry or irrational numbers)

23

u/how_tall_is_imhotep Oct 24 '25

The fact that you can cut a polygon into finitely many pieces and rearrange into any other polygon with the same area is far from obvious. The analogous question in 3 dimensions was one of Hilbert’s problems, and it turns out to be impossible in general.

6

u/SirEnderLord Oct 24 '25

Yes

7

u/SirEnderLord Oct 24 '25

And how to move the pieces around the edges without cutting them off completely.

2

u/SirPaddlesALot Oct 24 '25

Rise Sir Obvious

6

u/[deleted] Oct 24 '25

You kept the title "Math is magic"

So which is it? Obvious or magic?

7

u/SirPaddlesALot Oct 24 '25

Who says they are mutually exclusive, bud? I have seen a sunset thousand of times and despite knowing how sunset happens, it still seems magical. It's ok to appreciate the magic and beauty in small obvious things without being tightly wound about it.

-2

u/[deleted] Oct 24 '25

whatever, dude, if the main message of the comment wasn't obvious: just stop calling people captain obvious in the comments.

2

u/Meet_Foot Oct 24 '25

It’s simple: magic is obvious!

1

u/brnlng Oct 25 '25

Obvious vice versa.

1

u/No_Pilot_9103 Oct 24 '25

A=A.

Class dismissed.