# Vertical angles 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:

### Practice set

Problem 1A
Are $\angle APD$ and $\angle CPB$ vertical angles?
All segments that appear straight are straight.
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.
$\pink{\text{pink angle}} = 180^{\circ} - \blue{121^{\circ}} = \green{59^{\circ}}$
The pink and green angles also add up to $180^\circ$ because they are adjacent and form a straight line too.
$\green{\text{green angle}}= 180^{\circ} - \pink{59^{\circ}} = \green{121^{\circ}}$
The measure of angle $x=\green{121^{\circ}}$.

### Practice

Problem 2A
What is the measure of angle $x$?
$\Large{^\circ}$
Vertical angles are always equivalent!
Want to try more problems like this? Check out this exercise.