Definition of Linear Pair
- Linear Pair is a pair of adjacent angles that form a straight line.
More About Linear Pair
- The sum of the measure of the angles in a linear pair is supplementary or 180°.
- If one angle of a linear pair is acute (below 90o), then the other angle is obtuse (above 90o).
Example of Linear Pair
- In the above figure, ∠1 and ∠2, ∠2 and ∠3, ∠3 and ∠4, and ∠4 and ∠1 are linear pairs, as any pair of these angles forms a straight line.
Solved Example on Linear Pair
If m∠CAB = 32, then find the m∠CAD in the figure shown.
Correct Answer: A
Step 1: If ∠DAB is a straight angle, then m∠CAD + m∠CAB = 180 [Angle Addition Postulate.]
Step 2: m∠CAD + 32° = 180° [Substitute.]
Step 3: m∠CAD = 148 [Simplify.]
Related Terms for Linear Pair
- Acute Angle
- Adjacent Angles
- Obtuse Angle
- Straight Line
- Supplementary Angles