linear pair


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.

Choices:
A. 148
B. 212
C. 158
D. 32
Correct Answer: A
Solution:
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
  • Angle
  • Adjacent Angles
  • Line
  • Obtuse Angle
  • Pair
  • Straight Line
  • Supplementary Angles