$
  {\text{Fill in the blanks:}} \\
  {\text{Two angles forming a linear pair are:}} \\
 $

$
    \\
  {\text{Two angles forming a linear pair are: supplementary }} \\
    \\
  {\text{Note: We know that a linear pair of angles is formed when}} \\
  {\text{ two lines intersect each other}}{\text{. The measure of a}} \\
  {\text{ straight angle is 18}}{{\text{0}}^ \circ }{\text{ ,so a linear pair of}} \\
  {\text{ angles must add up to 18}}{{\text{0}}^ \circ } \\
 $