Flat (geometry)

Imagine you have a piece of paper. It has two sides, a front and a back. The paper is also flat, which means it doesn't stick up or down in any places.

In geometry, "flat" means the same thing. When we talk about a flat shape, like a triangle or a square, we are talking about shapes that are drawn on a flat surface, like a piece of paper.

When we draw these shapes, we use lines to show the edges of the shape. These lines are straight and they don't curve or bend.

So, when we talk about something being flat in geometry, we mean that it is a shape that can be drawn on a piece of paper with straight lines and without any parts sticking up or down.