To find the length of a line segment, given the coordinates of its endpoints, we can use two methods.

**Example**

Find the **length **of the line segment **AC** whose endpoints are at**:**

**A(-5, -3)** and **C(3, -3)**.

**Method 1**

Plot the points and count the squares.

This is a good method if you have time to do it and paper and pencil to hand!

AC is 8** **units** **long. Just write **8**

**Method 2**

If you don't have the time to plot the coordinates, this method is the best!

**Subtract **the relevant coordinates.

The **x-coordinates** of the endpoints of** vertical **lines will be the same.

The **y-coordinates** of the endpoints of **horizontal*** *lines will be the same.

**A is at (-5, -3)** and **C is at (3, -3)**.

The line AC is horizontal because the y-coordinates are both -3.

Subtract the x-coordinates: **-5** - **3** = -8 or **3** - **-5** = 8.

Ignore the sign: -8 or 8 means a length of 8** **units. Just write **8**.

For vertical lines, we would subtract the y-coordinates.

Let's give it a try in some questions now.