Annulus theorem
Imagine you have a circle, like a big round cookie. Now imagine you draw another circle inside it, but not touching the edges. This is like having a smaller cookie inside the bigger one. The space between the two circles is called the annulus.
The annulus theorem says that if you have a shape, like a square or a triangle, and you draw a circle inside it so that it doesn't touch the edges of the shape, and then draw another circle around the shape so that it touches all the corners, the area between the two circles is always the same, no matter what shape you started with.
This is kind of like if you have a toy box and you put a small toy inside it, and then put a bigger toy around the box that touches all the corners. The space between the two toys will always be the same, no matter what kind of toys you started with.
So the annulus theorem is just a fancy way of saying that the space between two circles of different sizes is always the same, no matter what shapes they're inside.
The annulus theorem says that if you have a shape, like a square or a triangle, and you draw a circle inside it so that it doesn't touch the edges of the shape, and then draw another circle around the shape so that it touches all the corners, the area between the two circles is always the same, no matter what shape you started with.
This is kind of like if you have a toy box and you put a small toy inside it, and then put a bigger toy around the box that touches all the corners. The space between the two toys will always be the same, no matter what kind of toys you started with.
So the annulus theorem is just a fancy way of saying that the space between two circles of different sizes is always the same, no matter what shapes they're inside.