Definition of Linear Pairs

Linear pairs are basically two angles that are adjacent and form a line. Adjacent simply means that they share a side.

Source

<1 and <4 form a linear pair.
Linear pairs are supplementary angles,meaning that when added together the form 180 degrees. One thing that you have to remember is that linear pairs  have to form lines. <1 and<4 form line l.

<1 and <3 form a linear pair. They form line t.
<2 and <7 form a linear pair. They form line m.

There are a few more, see if you can find them!

If you have any questions than comment!