Definition:Vertical Angles

Definition

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

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

Sources

• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): opposite: 3.
• 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): vertical angles (vertical opposite angles)