what is a linear pair of angles

Question

i need to know what this means

Answer 1

sum av 2 angels=180 deg=strate line

in orhter werds, line 2 hit line 1 & form 2 angels

Answer 2

Linear angles are two adjacent angles at the the intersection of two straight lines. Linear angles add up to 180 degrees (i.e., are supplementary angles). See first source. 

Vertical angles are two angles opposite to one another at the intersection of two straight lines. Vertical angles are equal to one another (are congruent). See second source.