Annulus (geometry)

Okay kiddo, an annulus is like a donut shape! It's made up of two circles - one big one and one smaller one - and the space in between them. Imagine taking a piece of paper and tracing a big circle and a smaller circle inside of it. Then you cut out the middle part and you're left with an annulus!

The big circle is called the "outer circle" and the smaller one is called the "inner circle." The distance between the two circles is called the "width" of the annulus.

Annuli are often used in geometry to calculate things like the area and circumference. To find the area, you can use a formula that involves both the outer and inner circles. To find the circumference, you just add together the lengths of the two circles.

So, now you know all about annuli! Next time you eat a donut, you can impress your friends by telling them all about the annulus shape!