# What are the properties of vertically opposite angles?

**Angles**and parallel lines. When two lines intersect they form two pairs of

**opposite angles**, A + C and B + D. Another word for

**opposite angles**are

**vertical angles**.

**Vertical angles**are always congruent, which means that they are equal.

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Keeping this in consideration, what is vertically opposite angles?

**Vertically Opposite Angles** are the **angles opposite** each other when two lines cross. "**Vertical**" in this case means they share the same Vertex (corner point), not the usual meaning of up-down.

One may also ask, are vertical angles and opposite angles the same thing? **Opposite angles**, **angles** that are **opposite** each other when two lines cross, are also known as **vertical angles** because the two **angles** share the **same** corner. **Opposite angles** are also congruent **angles**, meaning they are equal or have the **same** measurement.

Likewise, people ask, what are the properties of vertical angles?

Whenever two lines intersect, they form two pairs of **vertical angles**. **Vertical angles** have a common vertex, but they are never adjacent **angles**. Finally, **vertical angles** are always congruent.

How do you prove vertically opposite angles?

Theorem: In a pair of intersecting lines the **vertically opposite angles** are equal. Proof: Consider two lines overleftrightarrow{AB} and overleftrightarrow{CD} which intersect each other at O. The two pairs of **vertical angles** are: i) ∠AOD and ∠COB ii) ∠AOC and ∠BOD as shown.