#### What is the formal definition of a line?

Answer:In Geometry, a line has 3 properties

- is straight (no curves)
- has no thickness
- is infinite (in other words, it goes forever and ever in both directions)

### What does that really mean?

**more on straight**: Lines must be straight or they would look like this.

**dots** : A line is made up by so many dots that when we draw the line, we make it solid. However, keep in mind that it's just an infinite number of dots.

** showing infinity** :We use arrows on the tips of the line to show that the line continues forever.

Unlike a line, a ray has one endpoint and continues forever in only one direction.

Unlike a line, a segment has two endpoints.