ELI5: Explain Like I'm 5

Circle–ellipse problem

The circle-ellipse problem is a tricky math problem that involves circles and ellipses.

Imagine you have a circle and an ellipse, and they are both the same size. When you try to fit the ellipse inside the circle, you might find that it doesn't fit perfectly. This is because the shape of an ellipse is different than that of a circle.

Even though the circle and the ellipse have the same size, they have different shapes. A circle is perfectly round, but an ellipse is like a stretched out circle - it is longer in one direction than the other.

When you try to fit the ellipse inside the circle, you have to decide how to position the ellipse. You could make it so that it fits perfectly in one direction, but not in the other. Or you could make it so that it fits perfectly in the other direction, but not the first one.

This is called the circle-ellipse problem because it involves trying to fit a different shape (ellipse) inside a shape that is perfectly round (circle). It is a difficult problem because there is no one perfect way to fit an ellipse inside a circle. You have to make compromises, and decide which direction you want the ellipse to fit best.

So, even though a circle and an ellipse can be the same size, they are not the same shape, and it can be tricky to fit them together perfectly.