Definition:Vertical Angles

Definition
When two straight lines intersect, the angles opposite each other are called vertical angles:


 * VerticalAngles.png

In the above diagram:
 * $\alpha$ and $\beta$ are vertical angles
 * $\gamma$ and $\delta$ are vertical angles.

Also known as
Vertical angles are also known as vertically opposite angles.

Also see

 * Vertical Angle Theorem