Adjacent Angle and Linear Pair: Definitions and Examples
FAQs on What Is the Difference Between Adjacent Angles and a Linear Pair?
1. What is the difference between adjacent angles and a linear pair?
Adjacent angles share a common side and vertex, while a linear pair is a special case where the two adjacent angles add up to 180°.
Key differences:
- Adjacent angles: Two angles sharing a vertex and a side, but sum can be any value.
- Linear pair: Always adjacent, but non-common arms (sides) form a straight line, so angle sum is exactly 180°.
- Every linear pair is adjacent, but not every adjacent angle forms a linear pair.
2. Define adjacent angles with example.
Adjacent angles are two angles that have a common side and vertex, but do not overlap.
For example:
- If ∠ABC and ∠CBD share vertex B and side BC without overlapping, they are adjacent angles.
3. What is meant by a linear pair of angles?
A linear pair is a pair of adjacent angles whose non-common sides are opposite rays (form a straight line).
Main features:
- Angles are adjacent (share vertex and a side).
- Non-common sides make a straight line.
- Sum of angles is exactly 180°.
4. Are all adjacent angles a linear pair? Why or why not?
Not all adjacent angles form a linear pair.
- Reason: For a linear pair, the non-common arms must form a straight line (angle sum 180°).
- Adjacent angles can have any angle sum and may not be on a straight line.
- Only when their non-common sides form a straight line are they a linear pair.
5. List the conditions for two angles to be a linear pair.
For two angles to be a linear pair:
- They must be adjacent (share a vertex and a common arm).
- Their non-common arms must form a straight line (opposite rays).
- The sum of the two angles is always 180°.
6. Can two obtuse angles form a linear pair?
No, two obtuse angles cannot form a linear pair.
- Reason: The sum of two obtuse angles is greater than 180°, but a linear pair must sum to 180°.
7. State two real-life examples of adjacent angles.
Real-life examples of adjacent angles:
- Hands of a clock making angles at the center (e.g., at 3 o’clock, minute and hour hand form adjacent angles).
- Window panes meeting at a corner also form adjacent angles at the intersection.
8. How can you identify if two angles form a linear pair in a figure?
To identify a linear pair:
- Check they are adjacent (common vertex and side).
- Their non-common arms should make a straight line.
- If the two angles together make a straight angle (line), they form a linear pair (sum = 180°).
9. If the sum of two adjacent angles is 180°, what are they called?
If two adjacent angles have a sum of 180°, they are called a linear pair.
- They share a vertex and side, and their non-common arms form a straight line.
10. What is the main difference between a pair of complementary angles and a linear pair?
The main difference:
- Complementary angles sum to 90° (right angle); they need not be adjacent or form a straight line.
- Linear pairs must be adjacent, with non-common arms forming a straight line and sum 180°.






















