How to Identify Adjacent and Vertical Angles with Examples
FAQs on What Is the Difference Between Adjacent and Vertical Angles?
1. What is the difference between adjacent and vertical angles?
Adjacent angles share a common side and vertex but do not overlap, while vertical angles are opposite each other when two lines cross.
Key points:
- Adjacent angles have a common arm and vertex, and are side-by-side.
- Vertical angles are formed when two lines intersect and their arms form two pairs of opposite angles.
- Vertical angles are always equal; adjacent angles may or may not be equal.
2. What are adjacent angles?
Adjacent angles are two angles that share a common side and a common vertex, but do not overlap.
- They lie next to each other.
- They must not have any common interior points except the vertex.
- Examples are angles in a parallelogram or any straight line.
3. What are vertical angles?
Vertical angles are pairs of opposite angles formed when two lines cross or intersect each other.
- They share the same vertex, but are not adjacent.
- Vertical angles are always equal to each other.
- Also called vertically opposite angles.
4. Give an example of adjacent angles.
An example of adjacent angles is the pair created when a ray splits an angle into two smaller angles sharing a side.
- Angles ABC and CBD share common arm BC and vertex B.
- No overlap between the two angles.
5. Are all vertical angles congruent?
Yes, all vertical angles are always congruent.
- This means they have the same measure.
- This is true for any two lines that intersect.
- For example, if lines AB and CD intersect at O, angle AOC = BOD.
6. Can adjacent angles be supplementary?
Adjacent angles can be supplementary if their sum is 180 degrees.
- Such pairs are called a linear pair.
- For example, if two adjacent angles on a straight line sum up to 180°, they are supplementary.
7. What is the difference between adjacent and vertically opposite angles?
Adjacent angles share a side and vertex and are side by side; vertically opposite angles are formed by intersection and are always equal.
- Adjacent angles: Next to each other, possibly different measures.
- Vertically opposite angles: Opposite each other when two lines cross, always equal.
8. What is a linear pair of angles?
A linear pair is a pair of adjacent angles whose non-common sides form a straight line.
- The sum of angles in a linear pair is always 180°.
- Linear pairs are always supplementary.
9. How do you identify vertical and adjacent angles in a diagram?
Vertical angles are formed opposite each other when two lines intersect; adjacent angles share a side and vertex.
- Look for intersecting lines—the opposite angles are vertical angles.
- Angles with a common arm and vertex, lying next to one another, are adjacent angles.
10. Can two adjacent angles be complementary?
Adjacent angles can be complementary if their measures add up to 90 degrees.
- Such pairs are adjacent, share a vertex and a side, and together form a right angle.
11. What is the sum of all angles at a point where two lines intersect?
The sum of all angles around a point where two lines intersect is always 360 degrees.
- This includes two pairs of vertical angles (each pair has equal angles).
- The angles pair up as supplements (180° each pair).
12. Do adjacent angles have to be equal?
Adjacent angles do not have to be equal; their sizes may differ.
- Equality is only required for vertically opposite angles, not adjacent angles.






















