# Vertical anglesÂ review

Review the basics of vertical angles, and try some practice problems.

## Vertical angles

**Vertical angles**are angles opposite each other where two lines cross.

For example, $\angle AXD$ and $\angle BXC$ are vertical angles in the following diagram:

*Want to learn more about vertical angles? Check out this video.*

### Practice set

*Want to try more problems like this? Check out this exercise.*

## Use vertical angles to find a missing angle measure

Let's look at an example.

**What is the measure of angle $x$?**

First, let's find the measure of the pink angle:

The pink and blue angles add up to $180^\circ$ because they are adjacent and form a straight line.

The pink and green angles also add up to $180^\circ$ because they are adjacent and form a straight line too.

**The measure of angle $x=\green{121^{\circ}}$**.

### Practice

*Want to try more problems like this? Check out this exercise.*