# Which of the following is the best definition of a linear pair of angles?

# 1) A pair of supplementary angles is called a linear pair.

# 2) A pair of adjacent angles whose sum is equal to 180^{°}.

This is true that the angles forming a linear pair sum up to 180^{°} but they need not be a pair of supplementary angle.

## Answer: Linear pair is defined as a pair of adjacent angles whose sum is equal to 180^{°}. Thus, Option 2) is correct.

Let us understand the definition of a linear pair of angles.

**Explanation:**

Linear pair angles are formed by two intersecting lines. The pair is adjacent and their sum is equal to 180^{°}.

Look at the figure shown below. ∠1 and ∠2 form a pair of linear angles.

i.e, ∠1 + ∠2 = 180^{°}

But every pair of supplementary angles can't be a linear pair. The angles 75° and 105° form a pair of supplementary angles but they do not form a linear pair because they are not adjacent.